module: Sync code of is_arm_mapping_symbol()

After commit 2e3a10a1 ("ARM: avoid ARM binutils leaking ELF local
symbols") and commit d6b73266 ("modpost: fix undefined behavior of
is_arm_mapping_symbol()"), many differences of is_arm_mapping_symbol()
exist in kernel/module/kallsyms.c and scripts/mod/modpost.c, just sync
the code to keep consistent.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>