gdbserver: use common hexify/unhexify routines

Change-Id: I9989b625666e9c60ec9867cf6f4d94f41c998c3f
Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>
Reviewed-on: http://openocd.zylin.com/1105
Tested-by: jenkins
Reviewed-by: Mathias Küster <kesmtp@freenet.de>
Reviewed-by: Øyvind Harboe <oyvindharboe@gmail.com>

src/rtos/rtos.h

@@ -101,6 +101,5 @@ int rtos_update_threads(struct target *target);
 int rtos_smp_init(struct target *target);
 /*  function for handling symbol access */
 int rtos_qsymbol(struct connection *connection, char *packet, int packet_size);
-int str_to_hex(char *hex_dst, char *src);
 
 #endif	/* RTOS_H */