MIPS: Mark check_bugs() as __init

MIPS: Mark check_bugs() as __init

After commit ac7c3e4ff401 ("compiler: enable CONFIG_OPTIMIZE_INLINING
forcibly"), a compiler may choose not to inline a function marked with
just 'inline'. If check_bugs() is not inlined into start_kernel(), which
occurs when building with clang after commit 9ea7e6b62c2b ("init: Mark
[arch_call_]rest_init() __noreturn"), modpost complains with:

  WARNING: modpost: vmlinux.o: section mismatch in reference: check_bugs (section: .text) -> check_bugs32 (section: .init.text)

check_bugs() is only called from start_kernel(), which itself is marked
__init, so there would not be any issues at run time. Make it obvious to
modpost that this call chain is safe by marking check_bugs() as __init,
which fixes the warning.

Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Link: https://lore.kernel.org/CA+G9fYt+4e57Gdy6cix=LeNK6XqWoui8du=mZWu=cf8vPYocKw@mail.gmail.com/
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>