Bump minimum linux compat version to support Centos6 ports updates for linux.

Update linux compat minimum revision to match linux-c6 now in ports.  This
is a candidate for 10.1 R as it matches the current state of supported
linux compat packages in the ports tree.

PR:		187786
Reviewed by:	xmj
MFC after:	2 days
Relnotes:	yes
Fix build for kernels without COMPAT_FREEBSD32.