usb: throw away custom hex digit methods

Recent kernel has common method to convert hex digit to its value.

Signed-off-by: Andy Shevchenko <ext-andriy.shevchenko@nokia.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/gadget/u_ether.c b/drivers/usb/gadget/u_ether.c
index 1da755a..6bb876d 100644
--- a/drivers/usb/gadget/u_ether.c
+++ b/drivers/usb/gadget/u_ether.c
@@ -704,17 +704,6 @@
 module_param(host_addr, charp, S_IRUGO);
 MODULE_PARM_DESC(host_addr, "Host Ethernet Address");
 
-
-static u8 __init nibble(unsigned char c)
-{
-	if (isdigit(c))
-		return c - '0';
-	c = toupper(c);
-	if (isxdigit(c))
-		return 10 + c - 'A';
-	return 0;
-}
-
 static int get_ether_addr(const char *str, u8 *dev_addr)
 {
 	if (str) {
@@ -725,8 +714,8 @@
 
 			if ((*str == '.') || (*str == ':'))
 				str++;
-			num = nibble(*str++) << 4;
-			num |= (nibble(*str++));
+			num = hex_to_bin(*str++) << 4;
+			num |= hex_to_bin(*str++);
 			dev_addr [i] = num;
 		}
 		if (is_valid_ether_addr(dev_addr))