x86, tsc: Skip TSC synchronization checks for tsc=reliable

x86, tsc: Skip TSC synchronization checks for tsc=reliable

Orabug: 13256166
(mainline commit 28a00184be261e3dc152ba0d664a067bbe235b6a)
tsc=reliable boot parameter is supposed to skip all the TSC
stablility checks during boot time.

On a 8-socket system where we want to run an experiment with the
"tsc=reliable" boot option, TSC synchronization checks are not
getting skipped and marking the TSC as not stable.

Check for tsc_clocksource_reliable (which is set via
tsc=reliable or for platforms supporting synthetic TSC_RELIABLE
feature bit etc) and when set, skip the TSC synchronization
tests during boot.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: John Stultz <johnstul@us.ibm.com>
Tested-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1320446537.15071.14.camel@sbsiddha-desk.sc.intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Maxim Uvarov <maxim.uvarov@oracle.com>
Conflicts:
	arch/x86/include/asm/tsc.h