USB: move usb_translate_errors to linux/usb.h

Move usb_translate_errors from usb core to linux/usb.h as it is meant to
be accessed from drivers.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/include/linux/usb.h b/include/linux/usb.h
index d3d0c13..2f05a7f 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -1598,6 +1598,19 @@
 
 /* ----------------------------------------------------------------------- */
 
+/* translate USB error codes to codes user space understands */
+static inline int usb_translate_errors(int error_code)
+{
+	switch (error_code) {
+	case 0:
+	case -ENOMEM:
+	case -ENODEV:
+		return error_code;
+	default:
+		return -EIO;
+	}
+}
+
 /* Events from the usb core */
 #define USB_DEVICE_ADD		0x0001
 #define USB_DEVICE_REMOVE	0x0002