When we collect just user events for autofdo with lbr we get some events where branch
sources are kernel addresses and branch targets are user addresses. Without kernel MMAP
events create_gcov can't make sense of kernel addresses. Currently create_gcov fails if
it can't map at least 95% of events. We sometimes get below this threshold with just
user events. The change is to collect both user events and kernel events.

Tested on x86_64-pc-linux-gnu.

ChangeLog:

	* Makefile.in: Collect both kernel and user events for autofdo
	* Makefile.tpl: Collect both kernel and user events for autofdo

gcc/testsuite/ChangeLog:

	* lib/target-supports.exp: Collect both kernel and user events for autofdo