cmake: sysbuild: Remove unused variable

This variable is not used and the config item doesn't exist anyhow

Signed-off-by: Jamie McCrae <[email protected]>

Author: nordicjm

cmake/sysbuild/sign.cmake

@@ -106,7 +106,6 @@ function(b0_sign_image slot cpunet_target)
       # If slot is a target of it's own, then it means we target the hex directly and not a merged hex.
       sysbuild_get(${slot}_image_dir IMAGE ${slot} VAR APPLICATION_BINARY_DIR CACHE)
       sysbuild_get(${slot}_kernel_name IMAGE ${slot} VAR CONFIG_KERNEL_BIN_NAME KCONFIG)
-      sysbuild_get(${slot}_kernel_elf IMAGE ${slot} VAR CONFIG_KERNEL_ELF_NAME KCONFIG)
       sysbuild_get(${slot}_crypto_id IMAGE ${slot} VAR CONFIG_SB_VALIDATION_INFO_CRYPTO_ID KCONFIG)
       sysbuild_get(${slot}_validation_offset IMAGE ${slot} VAR CONFIG_SB_VALIDATION_METADATA_OFFSET KCONFIG)