doxygen: use correct comment syntax

This issue was caused by uncrustify not correctly converting the doxygen
comments.

Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>
Change-Id: Ie6dc3b057a08603b670cb27312e5f0d989426e6c
Reviewed-on: http://openocd.zylin.com/431
Tested-by: jenkins

src/helper/binarybuffer.c

@@ -238,7 +238,7 @@ char *buf_to_str(const void *_buf, unsigned buf_len, unsigned radix)
 	return str;
 }
 
-/* / identify radix, and skip radix-prefix (0, 0x or 0X) */
+/** identify radix, and skip radix-prefix (0, 0x or 0X) */
 static void str_radix_guess(const char **_str, unsigned *_str_len,
 	unsigned *_radix)
 {