selinux: inline avc_audit() and avc_has_perm_noaudit() into caller

Now that all the slow-path code is gone from these functions, we can
inline them into the main caller - avc_has_perm_flags().

Now the compiler can see that 'avc' is allocated on the stack for this
case, which helps register pressure a bit.  It also actually shrinks the
total stack frame, because the stack frame that avc_has_perm_flags()
always needed (for that 'avc' allocation) is now sufficient for the
inlined functions too.

Inlining isn't bad - but mindless inlining of cold code (see the
previous commit) is.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>