aarch64: Limit Arm SPE probes to PMU events

The autoprofile bootstrap support probes for Arm SPE from gcc/configure,
gcc-auto-profile, and the profile-optimization testsuite support.  Each
bare "perf list" scans every event class even though arm_spe is a PMU.
This can make the probe unnecessarily slow on systems with many events.

Use "perf list pmu" at all three call sites.  The PMU event class filter
has long been supported by perf and still reports arm_spe.  Stubbed BRBE,
SPE, and fallback paths select the same profiler as before.

This patch actually saves a few minutes of end-to-end bootstrap time on my SPE
AArch64 many-core system.

gcc/ChangeLog:

	* config/aarch64/gcc-auto-profile: Probe for arm_spe with
	"perf list pmu" instead of "perf list".
	* configure.ac: Likewise.
	* configure: Regenerate.

gcc/testsuite/ChangeLog:

	* lib/profopt.exp: Likewise.

Signed-off-by: Kyrylo Tkachov <ktkachov@nvidia.com>