mailbox: rockchip: drop of_match_ptr for ID table

The driver can match only via the DT table so the table should be always
used and the of_match_ptr does not have any sense (this also allows ACPI
matching via PRP0001, even though it might not be relevant here).

  drivers/mailbox/rockchip-mailbox.c:158:34: error: ‘rockchip_mbox_of_match’ defined but not used [-Werror=unused-const-variable=]

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

Author: krzk

drivers/mailbox/rockchip-mailbox.c

@@ -248,7 +248,7 @@ static struct platform_driver rockchip_mbox_driver = {
 	.probe	= rockchip_mbox_probe,
 	.driver = {
 		.name = "rockchip-mailbox",
-		.of_match_table = of_match_ptr(rockchip_mbox_of_match),
+		.of_match_table = rockchip_mbox_of_match,
 	},
 };