x86, mrst: Fix whitespace breakage in apb_timer.c

Checkin bb24c471:
"Moorestown APB system timer driver" suffered from severe whitespace
damage in arch/x86/kernel/apb_timer.c due to using Microsoft Lookout
to send a patch.  Fix the whitespace breakage.

Reported-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>