perf/x86/kvm: Add Cascade Lake Xeon steppings to isolation_ucodes[]

Cascade Lake Xeon parts have the same model number as Skylake Xeon
parts, so they are tagged with the intel_pebs_isolation
quirk. However, as with Skylake Xeon H0 stepping parts, the PEBS
isolation issue is fixed in all microcode versions.

Add the Cascade Lake Xeon steppings (5, 6, and 7) to the
isolation_ucodes[] table so that these parts benefit from Andi's
optimization in commit 9b545c04 ("perf/x86/kvm: Avoid unnecessary
work in guest filtering").
Signed-off-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NAndi Kleen <ak@linux.intel.com>
Link: https://lkml.kernel.org/r/20210205191324.2889006-1-jmattson@google.com

arch/x86/events/intel/core.c

@@ -4513,6 +4513,9 @@ static const struct x86_cpu_desc isolation_ucodes[] = {
 	INTEL_CPU_DESC(INTEL_FAM6_BROADWELL_X,		 2, 0x0b000014),
 	INTEL_CPU_DESC(INTEL_FAM6_SKYLAKE_X,		 3, 0x00000021),
 	INTEL_CPU_DESC(INTEL_FAM6_SKYLAKE_X,		 4, 0x00000000),
+	INTEL_CPU_DESC(INTEL_FAM6_SKYLAKE_X,		 5, 0x00000000),
+	INTEL_CPU_DESC(INTEL_FAM6_SKYLAKE_X,		 6, 0x00000000),
+	INTEL_CPU_DESC(INTEL_FAM6_SKYLAKE_X,		 7, 0x00000000),
 	INTEL_CPU_DESC(INTEL_FAM6_SKYLAKE_L,		 3, 0x0000007c),
 	INTEL_CPU_DESC(INTEL_FAM6_SKYLAKE,		 3, 0x0000007c),
 	INTEL_CPU_DESC(INTEL_FAM6_KABYLAKE,		 9, 0x0000004e),