compiler: enable CONFIG_OPTIMIZE_INLINING forcibly

compiler: enable CONFIG_OPTIMIZE_INLINING forcibly

Commit 9012d011660e ("compiler: allow all arches to enable
CONFIG_OPTIMIZE_INLINING") allowed all architectures to enable this
option.  A couple of build errors were reported by randconfig, but all of
them have been ironed out.

Towards the goal of removing CONFIG_OPTIMIZE_INLINING entirely (and it
will simplify the 'inline' macro in compiler_types.h), this commit changes
it to always-on option.  Going forward, the compiler will always be
allowed to not inline functions marked 'inline'.

This is not a problem for x86 since it has been long used by
arch/x86/configs/{x86_64,i386}_defconfig.

I am keeping the config option just in case any problem crops up for other
architectures.

The code clean-up will be done after confirming this is solid.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Masahiro Yamada <[email protected]>
Acked-by: Nick Desaulniers <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Miguel Ojeda <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>