arm64: perf: Correct Cortex-A53/A57 compatible values

Use commas instead of periods.
Acked-by: NMark Rutland <mark.rutland@arm.com>
Acked-by: NDirk Behme <dirk.behme@gmail.com>
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Documentation/devicetree/bindings/arm/pmu.txt

@@ -9,8 +9,8 @@ Required properties:
 - compatible : should be one of
 	"apm,potenza-pmu"
 	"arm,armv8-pmuv3"
-	"arm.cortex-a57-pmu"
-	"arm.cortex-a53-pmu"
+	"arm,cortex-a57-pmu"
+	"arm,cortex-a53-pmu"
 	"arm,cortex-a17-pmu"
 	"arm,cortex-a15-pmu"
 	"arm,cortex-a12-pmu"