Clang does not support this machine dependent option.

Older versions of GCC (pre 3.0) may not support this option, added in
2000, but it's unlikely they can still compile a working kernel.
Signed-off-by: Nick Desaulniers <nick.desaulniers@gmail.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170509032946.20444-1-nick.desaulniers@gmail.comSigned-off-by: Ingo Molnar <mingo@kernel.org>