CMake: GCC ARM linker script fix

Fixes https://github.com/ARMmbed/mbed-os/issues/13983
Move linker script to the function mbed_set_mbed_target_linker_script.

I also moved memmap as it is needed for an app. The location might not be the best fit,
we will address this in separate pull request.

CMakeLists.txt

@@ -141,6 +141,11 @@ function(mbed_set_mbed_target_linker_script target)
             WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
             BYPRODUCTS "${CMAKE_BINARY_DIR}/${target}.link_script.ld"
         )
+        target_link_options(mbed-core
+            INTERFACE
+                "-T" "${CMAKE_BINARY_DIR}/${target}.link_script.ld"
+                "-Wl,-Map=${CMAKE_BINARY_DIR}/${target}.map"
+        )
     elseif(MBED_TOOLCHAIN STREQUAL "ARM")
         set(CMAKE_PRE_BUILD_COMMAND COMMAND "")
         target_link_options(mbed-core

tools/cmake/toolchains/GCC_ARM.cmake

@@ -19,8 +19,6 @@ function(mbed_set_toolchain_options target)
             "-lnosys"
         "-Wl,--end-group"
         "-specs=nosys.specs"
-        "-T" "${CMAKE_BINARY_DIR}/${APP_TARGET}.link_script.ld"
-        "-Wl,-Map=${CMAKE_BINARY_DIR}/${APP_TARGET}.map"
         "-Wl,--cref"
     )