merge pam_decode_frame() into pnm_decode_frame()
merge pam_decode_frame() into pnm_decode_frame()


git-svn-id: a4d7c1866f8397a4106e0b57fc4fbf792bbdaaaf@3677 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

prajnashi/ffmpeg,prajnashi/ffmpeg,prajnashi/ffmpeg,prajnashi/ffmpeg