suppress unnecessary makefile output

checkpolicy spits out a bunch of unnecessary lines during normal
operation, which bloat the logs and hide other more important
warnings. Suppress the normal output.

SELinux compile time errors are printed to stderr, and are
uneffected by this change.

Change-Id: I07f2cbe8afcd14abf1c025355a169b5214ed5c6e
1 file changed