elf(bugfix):fix elf compile link error when enable LTO

fix compilation errors when enabling the LTO linker

Signed-off-by: xuxin19 <xuxin19@xiaomi.com>

arch/arm/src/cmake/elf.cmake

@@ -38,6 +38,12 @@ nuttx_mod_link_options(-r)
 
 nuttx_elf_link_options_ifdef(CONFIG_BUILD_KERNEL -Bstatic)
 
-nuttx_elf_link_options_ifdef(CONFIG_DEBUG_OPT_UNUSED_SECTIONS --gc-sections)
+if(CONFIG_DEBUG_OPT_UNUSED_SECTIONS)
+  if("${CMAKE_LD}" MATCHES "gcc$")
+    nuttx_elf_link_options(-Wl,--gc-sections)
+  else()
+    nuttx_elf_link_options(--gc-sections)
+  endif()
+endif()
 
 nuttx_elf_link_options(-e __start)