iio:accel:stk8312: Add lowercase i2c device id

These are never upper case.  Chances are that all users of this driver
were using the ACPI binding but just in case keep the uppercase version
but mark it deprecated.

Whilst here tidy up some spacing.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20210401144226.225928-1-jic23@kernel.org

drivers/iio/accel/stk8312.c

@@ -635,13 +635,15 @@ static SIMPLE_DEV_PM_OPS(stk8312_pm_ops, stk8312_suspend, stk8312_resume);
 #endif
 
 static const struct i2c_device_id stk8312_i2c_id[] = {
-	{"STK8312", 0},
+	/* Deprecated in favour of lowercase form */
+	{ "STK8312", 0 },
+	{ "stk8312", 0 },
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, stk8312_i2c_id);
 
 static const struct acpi_device_id stk8312_acpi_id[] = {
-	{"STK8312", 0},
+	{ "STK8312", 0 },
 	{}
 };