x86/mce: Drop X86_FEATURE_MCE_RECOVERY and the related model string test

We now have a better way to determine if we are running on a cpu that
supports machine check recovery. Free up this feature bit.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Boris Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/d5db39e08d46cf1012d94d3902275d08ba931926.1472754712.git.tony.luck@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>