regtest: simplify encoding functions

The video encoding options were needlessly split in two parameters
which are merged.  The do_audio_encoding function did not use its
second argument, so this can be removed.
Signed-off-by: Mans Rullgard <mans@mansr.com>

tests/regression-funcs.sh

@@ -121,13 +121,13 @@ do_video_decoding()
 do_video_encoding()
 {
     file=${outfile}$1
-    do_ffmpeg $file $2 -f image2 -vcodec pgmyuv -i $raw_src $3
+    do_ffmpeg $file -f image2 -vcodec pgmyuv -i $raw_src $2
 }
 
 do_audio_encoding()
 {
     file=${outfile}$1
-    do_ffmpeg $file -ab 128k -ac 2 -f s16le -i $pcm_src $3
+    do_ffmpeg $file -ab 128k -ac 2 -f s16le -i $pcm_src $2
 }
 
 do_audio_decoding()