MIPS: Sink body of check_bugs_early() into its only call site

If check_bugs_early() is not inlined, which a compiler is free to do
after commit ac7c3e4f ("compiler: enable CONFIG_OPTIMIZE_INLINING
forcibly"), modpost would warn that check_bugs_early(), a non-init
function, refers to check_bugs64_early(), which is marked __init. This
would not result in any run time issues, as check_bugs_early() is only
called from setup_arch(), which is marked __init.

To avoid this potential warning, just sink the body of
check_bugs_early() into its single call site in setup_arch().

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>