kselftest/arm64: Refactor parameter checking in mte_switch_mode()

Currently we just have a big if statement with a non-specific diagnostic
checking both the mode and the tag. Since we'll need to dynamically check
for asymmetric mode support in the system and to improve debugability split
these checks out.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220419103243.24774-4-broonie@kernel.orgSigned-off-by: Catalin Marinas <catalin.marinas@arm.com>

tools/testing/selftests/arm64/mte/mte_common_util.c

@@ -273,9 +273,18 @@ int mte_switch_mode(int mte_option, unsigned long incl_mask)
 {
 	unsigned long en = 0;
 
-	if (!(mte_option == MTE_SYNC_ERR || mte_option == MTE_ASYNC_ERR ||
-	      mte_option == MTE_NONE_ERR || incl_mask <= MTE_ALLOW_NON_ZERO_TAG)) {
-		ksft_print_msg("FAIL: Invalid mte config option\n");
+	switch (mte_option) {
+	case MTE_NONE_ERR:
+	case MTE_SYNC_ERR:
+	case MTE_ASYNC_ERR:
+		break;
+	default:
+		ksft_print_msg("FAIL: Invalid MTE option %x\n", mte_option);
+		return -EINVAL;
+	}
+
+	if (!(incl_mask <= MTE_ALLOW_NON_ZERO_TAG)) {
+		ksft_print_msg("FAIL: Invalid incl_mask %lx\n", incl_mask);
 		return -EINVAL;
 	}
 	en = PR_TAGGED_ADDR_ENABLE;