gst/law/: Some cleanups in the chain functions.

gst/law/: Some cleanups in the chain functions.

Original commit message from CVS:
* gst/law/alaw-decode.c: (gst_alawdec_chain):
* gst/law/alaw-decode.h:
* gst/law/alaw-encode.c: (gst_alawenc_chain):
* gst/law/alaw-encode.h:
* gst/law/mulaw-decode.c: (gst_mulawdec_chain):
* gst/law/mulaw-decode.h:
* gst/law/mulaw-encode.c: (gst_mulawenc_chain):
* gst/law/mulaw-encode.h:
Some cleanups in the chain functions.
Remove some GStreamer 0.0.2 bits.