perf/x86/amd: Add missing L2 misses event spec to AMD Family 17h's event map

Commit 3fe3331b ("perf/x86/amd: Add event map for AMD Family 17h"),
claimed L2 misses were unsupported, due to them not being found in its
referenced documentation, whose link has now moved [1].

That old documentation listed PMCx064 unit mask bit 3 as:

    "LsRdBlkC: LS Read Block C S L X Change to X Miss."

and bit 0 as:

    "IcFillMiss: IC Fill Miss"

We now have new public documentation [2] with improved descriptions, that
clearly indicate what events those unit mask bits represent:

Bit 3 now clearly states:

    "LsRdBlkC: Data Cache Req Miss in L2 (all types)"

and bit 0 is:

    "IcFillMiss: Instruction Cache Req Miss in L2."

So we can now add support for L2 misses in perf's genericised events as
PMCx064 with both the above unit masks.

[1] The commit's original documentation reference, "Processor Programming
    Reference (PPR) for AMD Family 17h Model 01h, Revision B1 Processors",
    originally available here:

        https://www.amd.com/system/files/TechDocs/54945_PPR_Family_17h_Models_00h-0Fh.pdf

    is now available here:

        https://developer.amd.com/wordpress/media/2017/11/54945_PPR_Family_17h_Models_00h-0Fh.pdf

[2] "Processor Programming Reference (PPR) for Family 17h Model 31h,
    Revision B0 Processors", available here:

	https://developer.amd.com/wp-content/resources/55803_0.54-PUB.pdf

Fixes: 3fe3331b ("perf/x86/amd: Add event map for AMD Family 17h")
Reported-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Babu Moger <babu.moger@amd.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20200121171232.28839-1-kim.phillips@amd.com

arch/x86/events/amd/core.c

@@ -250,6 +250,7 @@ static const u64 amd_f17h_perfmon_event_map[PERF_COUNT_HW_MAX] =
 	[PERF_COUNT_HW_CPU_CYCLES]		= 0x0076,
 	[PERF_COUNT_HW_INSTRUCTIONS]		= 0x00c0,
 	[PERF_COUNT_HW_CACHE_REFERENCES]	= 0xff60,
+	[PERF_COUNT_HW_CACHE_MISSES]		= 0x0964,
 	[PERF_COUNT_HW_BRANCH_INSTRUCTIONS]	= 0x00c2,
 	[PERF_COUNT_HW_BRANCH_MISSES]		= 0x00c3,
 	[PERF_COUNT_HW_STALLED_CYCLES_FRONTEND]	= 0x0287,