psxstr: more correct array type.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/psxstr.c

@@ -64,7 +64,7 @@ typedef struct StrDemuxContext {
     StrChannel channels[32];
 } StrDemuxContext;
 
-static const char sync_header[12] = {0x00,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0x00};
+static const uint8_t sync_header[12] = {0x00,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0x00};
 
 static int str_probe(AVProbeData *p)
 {