Remove 2 ++ from check_pes() that are useless, found by CSA.

Originally committed as revision 18577 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/mpeg.c

@@ -42,10 +42,8 @@ static int check_pes(uint8_t *p, uint8_t *end){
     if((*p&0xC0) == 0x40) p+=2;
     if((*p&0xF0) == 0x20){
         pes1= p[0]&p[2]&p[4]&1;
-        p+=5;
     }else if((*p&0xF0) == 0x30){
         pes1= p[0]&p[2]&p[4]&p[5]&p[7]&p[9]&1;
-        p+=10;
     }else
         pes1 = *p == 0x0F;