powerpc/perf: Give generic PMU a nice name

When booting on a machine that uses the compat pmu driver we see this:

 [    0.071192] GENERIC_COMPAT performance monitor hardware support registered

Which is a bit shouty. Give it a nicer name.
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220610044006.2095806-1-joel@jms.id.au

arch/powerpc/perf/generic-compat-pmu.c

@@ -292,7 +292,7 @@ static int generic_compute_mmcr(u64 event[], int n_ev,
 }
 
 static struct power_pmu generic_compat_pmu = {
-	.name			= "GENERIC_COMPAT",
+	.name			= "ISAv3",
 	.n_counter		= MAX_PMU_COUNTERS,
 	.add_fields		= ISA207_ADD_FIELDS,
 	.test_adder		= ISA207_TEST_ADDER,