USB: ULPI: clean a mixup of return types

Clean a mixup between u32 and int as a return type
for functions returning error values.
Use int as it is native (and widely used) return type.

Signed-off-by: Igor Grinberg <grinberg@compulab.co.il>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/usb/ulpi/ulpi-viewport.c b/drivers/usb/ulpi/ulpi-viewport.c
index fa2e004..490fb0e 100644
--- a/drivers/usb/ulpi/ulpi-viewport.c
+++ b/drivers/usb/ulpi/ulpi-viewport.c
@@ -98,7 +98,7 @@
 	return err;
 }
 
-u32 ulpi_write(u32 ulpi_viewport, u8 *reg, u32 value)
+int ulpi_write(u32 ulpi_viewport, u8 *reg, u32 value)
 {
 	u32 val = ULPI_RWRUN | ULPI_RWCTRL | ((u32)reg << 16) | (value & 0xff);
 
@@ -107,7 +107,7 @@
 
 u32 ulpi_read(u32 ulpi_viewport, u8 *reg)
 {
-	u32 err;
+	int err;
 	u32 val = ULPI_RWRUN | ((u32)reg << 16);
 
 	err = ulpi_request(ulpi_viewport, val);