libipt: outline bounds check in pt_sync_*() functions
libipt: outline bounds check in pt_sync_*() functions

Each pt_sync_*() function checks whether the starting position lies within
the bounds of the trace buffer.  Outline this check into a helper function.

Change-Id: Iba4ac493a322733b90cf1e2c281eaa47e28889c6
Signed-off-by: Markus Metzger <5f675b2b36595f90898e014b548ff7d9bbff2ab7@intel.com>

shadown/processor-trace,breadbaconic/processor-trace,andikleen/processor-trace,andikleen/processor-trace,01org/processor-trace,01org/processor-trace,pombreda/processor-trace,breadbaconic/processor-trace,drupalhunter-team/processor-trace,hoangt/processor-trace,shadown/processor-trace,pombreda/processor-trace,hoangt/processor-trace,01org/processor-trace,drupalhunter-team/processor-trace