modules: tfm: Remove duplicate tfm cmakecache config

Remove duplicated setting of TF-M CMakeCache.txt entry TFM_BOARD.
In addition it is also wrong since the CONFIG_ prefix is missing.

Leftover from: 583d5a6

Signed-off-by: Joakim Andersson <[email protected]>

Author: joerchan

modules/trusted-firmware-m/CMakeLists.txt

@@ -191,7 +191,6 @@ if (CONFIG_BUILD_WITH_TFM)
       -DTFM_TOOLCHAIN_FILE=${ZEPHYR_TRUSTED_FIRMWARE_M_MODULE_DIR}/${TFM_TOOLCHAIN_FILE}
       -DPSA_TOOLCHAIN_FILE=${CMAKE_CURRENT_LIST_DIR}/psa/GNUARM.cmake
       -DTOOLCHAIN=INHERIT
-      -DTFM_PLATFORM=${TFM_BOARD}
       -DCROSS_COMPILE=${TFM_TOOLCHAIN_PATH}/${TFM_TOOLCHAIN_PREFIX}
       -DCMAKE_BUILD_TYPE=${TFM_CMAKE_BUILD_TYPE}
       -DTFM_PLATFORM=${CONFIG_TFM_BOARD}