coresight: etm4x: Add support to enable ETMv4.2

SDM845 has ETMv4.2 and can use the existing etm4x driver.
But the current etm driver checks only for ETMv4.0 and
errors out for other etm4x versions. This patch adds this
missing support to enable SoC's with ETMv4x to use same
driver by checking only the ETM architecture major version
number.

Without this change, we get below error during etm probe:

/ # dmesg | grep etm
[    6.660093] coresight-etm4x: probe of 7040000.etm failed with error -22
[    6.666902] coresight-etm4x: probe of 7140000.etm failed with error -22
[    6.673708] coresight-etm4x: probe of 7240000.etm failed with error -22
[    6.680511] coresight-etm4x: probe of 7340000.etm failed with error -22
[    6.687313] coresight-etm4x: probe of 7440000.etm failed with error -22
[    6.694113] coresight-etm4x: probe of 7540000.etm failed with error -22
[    6.700914] coresight-etm4x: probe of 7640000.etm failed with error -22
[    6.707717] coresight-etm4x: probe of 7740000.etm failed with error -22

With this change, etm probe is successful:

/ # dmesg | grep etm
[    6.659198] coresight-etm4x 7040000.etm: CPU0: ETM v4.2 initialized
[    6.665848] coresight-etm4x 7140000.etm: CPU1: ETM v4.2 initialized
[    6.672493] coresight-etm4x 7240000.etm: CPU2: ETM v4.2 initialized
[    6.679129] coresight-etm4x 7340000.etm: CPU3: ETM v4.2 initialized
[    6.685770] coresight-etm4x 7440000.etm: CPU4: ETM v4.2 initialized
[    6.692403] coresight-etm4x 7540000.etm: CPU5: ETM v4.2 initialized
[    6.699024] coresight-etm4x 7640000.etm: CPU6: ETM v4.2 initialized
[    6.705646] coresight-etm4x 7740000.etm: CPU7: ETM v4.2 initialized
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hwtracing/coresight/coresight-etm4x.c

@@ -55,7 +55,8 @@ static void etm4_os_unlock(struct etmv4_drvdata *drvdata)
 
 static bool etm4_arch_supported(u8 arch)
 {
-	switch (arch) {
+	/* Mask out the minor version number */
+	switch (arch & 0xf0) {
 	case ETM_ARCH_V4:
 		break;
 	default: