perf/events/amd/uncore: Fix amd_uncore_llc ID to use pre-defined cpu_llc_id

perf/events/amd/uncore: Fix amd_uncore_llc ID to use pre-defined cpu_llc_id

Current logic iterates over CPUID Fn8000001d leafs (Cache Properties)
to detect the last level cache, and derive the last-level cache ID.
However, this information is already available in the cpu_llc_id.
Therefore, make use of it instead.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Janakarajan Natarajan <Janakarajan.Natarajan@amd.com>
Link: http://lkml.kernel.org/r/1524864877-111962-3-git-send-email-suravee.suthikulpanit@amd.com
CVE-2018-3620
CVE-2018-3646

(cherry picked from commit 812af433038f984fd951224e8239b09188e36a13)
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>