Provide a binary to hex conversion function

Provide a function to convert a buffer of binary data into an unterminated
ascii hex string representation of that data.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>

include/linux/kernel.h

@@ -500,6 +500,7 @@ static inline char * __deprecated pack_hex_byte(char *buf, u8 byte)
 
 extern int hex_to_bin(char ch);
 extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
+extern char *bin2hex(char *dst, const void *src, size_t count);
 
 int mac_pton(const char *s, u8 *mac);