mfd: stmfx: 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/stmfx.c:542:34: warning: ‘stmfx_of_match’ defined but not used [-Wunused-const-variable=]
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/stmfx.c

@@ -548,7 +548,7 @@ MODULE_DEVICE_TABLE(of, stmfx_of_match);
 static struct i2c_driver stmfx_driver = {
 	.driver = {
 		.name = "stmfx-core",
-		.of_match_table = of_match_ptr(stmfx_of_match),
+		.of_match_table = stmfx_of_match,
 		.pm = &stmfx_dev_pm_ops,
 	},
 	.probe = stmfx_probe,