fix(linux): Escape OPTEE platform flavor substitution variable

Without this build instructions don't show substituted text. While at
that drop stray "k3-" prefix which is no longer required.

Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>

Author: r-vignesh

source/linux/Foundational_Components_OPTEE.rst

@@ -54,13 +54,13 @@ Building the OP-TEE image
 
    .. parsed-literal::
 
-      $ make CROSS_COMPILE="$CROSS_COMPILE_32" CROSS_COMPILE64="$CROSS_COMPILE_64" PLATFORM=|__OPTEE_PLATFORM_FLAVOR__| CFG_ARM64_core=y
+      $ make CROSS_COMPILE="$CROSS_COMPILE_32" CROSS_COMPILE64="$CROSS_COMPILE_64" PLATFORM=\ |__OPTEE_PLATFORM_FLAVOR__| CFG_ARM64_core=y
 
 .. ifconfig:: CONFIG_part_variant in ('AM62LX')
 
    .. parsed-literal::
 
-      $ make CROSS_COMPILE64="$CROSS_COMPILE_64" PLATFORM=|__OPTEE_PLATFORM_FLAVOR__| CFG_ARM64_core=y CFG_USER_TA_TARGETS=ta_arm64
+      $ make CROSS_COMPILE64="$CROSS_COMPILE_64" PLATFORM=\ |__OPTEE_PLATFORM_FLAVOR__| CFG_ARM64_core=y CFG_USER_TA_TARGETS=ta_arm64
 
 Building the OP-TEE image with debug parameters
 ***********************************************
@@ -69,13 +69,13 @@ Building the OP-TEE image with debug parameters
 
    .. parsed-literal::
 
-      $ make CROSS_COMPILE="$CROSS_COMPILE_32" CROSS_COMPILE64="$CROSS_COMPILE_64" PLATFORM=|__OPTEE_PLATFORM_FLAVOR__| CFG_ARM64_core=y CFG_TEE_CORE_LOG_LEVEL=2 CFG_TEE_CORE_DEBUG=y
+      $ make CROSS_COMPILE="$CROSS_COMPILE_32" CROSS_COMPILE64="$CROSS_COMPILE_64" PLATFORM=\ |__OPTEE_PLATFORM_FLAVOR__| CFG_ARM64_core=y CFG_TEE_CORE_LOG_LEVEL=2 CFG_TEE_CORE_DEBUG=y
 
 .. ifconfig:: CONFIG_part_variant in ('AM62LX')
 
    .. parsed-literal::
 
-      $ make CROSS_COMPILE64="$CROSS_COMPILE_64" PLATFORM=|__OPTEE_PLATFORM_FLAVOR__| CFG_ARM64_core=y CFG_TEE_CORE_LOG_LEVEL=2 CFG_TEE_CORE_DEBUG=y CFG_USER_TA_TARGETS=ta_arm64
+      $ make CROSS_COMPILE64="$CROSS_COMPILE_64" PLATFORM=\ |__OPTEE_PLATFORM_FLAVOR__| CFG_ARM64_core=y CFG_TEE_CORE_LOG_LEVEL=2 CFG_TEE_CORE_DEBUG=y CFG_USER_TA_TARGETS=ta_arm64
 
 .. _building-optee-with-prng:
 
@@ -91,13 +91,13 @@ of entropy can work around these issues.
 
    .. parsed-literal::
 
-      $ make CROSS_COMPILE="$CROSS_COMPILE_32" CROSS_COMPILE64="$CROSS_COMPILE_64" PLATFORM=k3-|__OPTEE_PLATFORM_FLAVOR__| CFG_ARM64_core=y CFG_WITH_SOFTWARE_PRNG=y
+      $ make CROSS_COMPILE="$CROSS_COMPILE_32" CROSS_COMPILE64="$CROSS_COMPILE_64" PLATFORM=\ |__OPTEE_PLATFORM_FLAVOR__| CFG_ARM64_core=y CFG_WITH_SOFTWARE_PRNG=y
 
 .. ifconfig:: CONFIG_part_variant in ('AM62LX')
 
    .. parsed-literal::
 
-      $ make CROSS_COMPILE64="$CROSS_COMPILE_64" PLATFORM=k3-|__OPTEE_PLATFORM_FLAVOR__| CFG_ARM64_core=y CFG_WITH_SOFTWARE_PRNG=y CFG_USER_TA_TARGETS=ta_arm64
+      $ make CROSS_COMPILE64="$CROSS_COMPILE_64" PLATFORM=\ |__OPTEE_PLATFORM_FLAVOR__| CFG_ARM64_core=y CFG_WITH_SOFTWARE_PRNG=y CFG_USER_TA_TARGETS=ta_arm64
 
 .. _secure-storage-with-rpmb:
 
@@ -151,7 +151,7 @@ encrypted binary blobs created by REE FS in
 
    .. parsed-literal::
 
-      $ make CROSS_COMPILE64="$CROSS_COMPILE_64" PLATFORM=|__OPTEE_PLATFORM_FLAVOR__| CFG_ARM64_core=y CFG_REE_FS=y CFG_RPMB_FS=y
+      $ make CROSS_COMPILE64="$CROSS_COMPILE_64" PLATFORM=\ |__OPTEE_PLATFORM_FLAVOR__| CFG_ARM64_core=y CFG_REE_FS=y CFG_RPMB_FS=y
 
    OPTEE-client also needs to be updated to enable the use of real
    emmc instead of the virtual emmc that is enabled by default