iio: imu: inv_mpu6050: Mark acpi match table as maybe unused

When building kernels without ACPI support the table is declared
but is not used because ACPI_PTR() turns it into a NULL.

Add the __maybe_unused attribute to stop the compiler whining.
Signed-off-by: Daniel Palmer <daniel@0x0f.com>
Acked-by: Jean-Baptiste Maneyrol <jmaneyrol@invensense.com>
Link: https://lore.kernel.org/r/20210913112913.2148026-1-daniel@0x0f.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/imu/inv_mpu6050/inv_mpu_i2c.c

@@ -249,7 +249,7 @@ static const struct of_device_id inv_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, inv_of_match);
 
-static const struct acpi_device_id inv_acpi_match[] = {
+static const struct acpi_device_id __maybe_unused inv_acpi_match[] = {
 	{"INVN6500", INV_MPU6500},
 	{ },
 };