aacparse: When parsing raw input, accept frames of any size

aacparse: When parsing raw input, accept frames of any size

Raw AAC streams might have very small frames, e.g. 6 byte frames
when encoding silence. These frames are then smaller than aacparse's
default min_frame_size of 10 bytes (ADTS_MAX_SIZE).

When passthrough is disabled or aacparse has to output ADTS, GstBaseParse
will concatenate these short frames to the following frame before
handling them to aacparse, which processes each input buffer as a single
frame, producing bad output.

To avoid this problem, set the min_frame_size to 1 when receiving a raw
stream.

https://bugzilla.gnome.org/show_bug.cgi?id=792644