usb: dwc2: fix dwc2_get_device_property for u8 and u16

According to the Devicetree ePAPR [1] the datatypes u8 and u16 are
not defined. So using device_property_read_u16() would result in
a partial read of a 32-bit big-endian integer which is not intended.
So we better read the complete 32-bit value. This fixes a regression
on bcm2835 where the values for g-rx-fifo-size and g-np-tx-fifo-size
always read as zero:

  Invalid value 0 for param g-rx-fifo-size
  Invalid value 0 for param g-np-tx-fifo-size

[1] - http://elinux.org/images/c/cf/Power_ePAPR_APPROVED_v1.1.pdf

Fixes: 05ee799f202 ("usb: dwc2: Move gadget settings into core_params")
Acked-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc2/params.c

@@ -247,8 +247,6 @@ MODULE_DEVICE_TABLE(of, dwc2_of_match_table);
 static void dwc2_get_device_property(struct dwc2_hsotg *hsotg,
 				     char *property, u8 size, u64 *value)
 {
-	u8 val8;
-	u16 val16;
 	u32 val32;
 
 	switch (size) {
@@ -256,17 +254,7 @@ static void dwc2_get_device_property(struct dwc2_hsotg *hsotg,
 		*value = device_property_read_bool(hsotg->dev, property);
 		break;
 	case 1:
-		if (device_property_read_u8(hsotg->dev, property, &val8))
-			return;
-
-		*value = val8;
-		break;
 	case 2:
-		if (device_property_read_u16(hsotg->dev, property, &val16))
-			return;
-
-		*value = val16;
-		break;
 	case 4:
 		if (device_property_read_u32(hsotg->dev, property, &val32))
 			return;