oss: Mark loadhex static in hex2hex.c

Nothing outside of hex2hex.c references loadhex.
Signed-off-by: Josh Triplett <josh@joshtriplett.org>

sound/oss/hex2hex.c

@@ -12,7 +12,7 @@
 #define MAX_SIZE (256*1024)
 unsigned char buf[MAX_SIZE];
 
-int loadhex(FILE *inf, unsigned char *buf)
+static int loadhex(FILE *inf, unsigned char *buf)
 {
 	int l=0, c, i;