mfd: wm8994: Drop of_match_ptr from of_device_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 is not relevant here). This fixes
compile warning (!CONFIG_OF on x86_64):

drivers/mfd/wm8994-core.c:618:34: warning: ‘wm8994_of_match’ defined but not used [-Wunused-const-variable=]

Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Acked-by: Charles Keepax <[e-mail]>
Signed-off-by: Lee Jones <[e-mail]>

drivers/mfd/wm8994-core.c

···
 	.driver = {
 		.name = "wm8994",
 		.pm = &wm8994_pm_ops,
-		.of_match_table = of_match_ptr(wm8994_of_match),
+		.of_match_table = wm8994_of_match,
 	},
 	.probe = wm8994_i2c_probe,
 	.remove = wm8994_i2c_remove,