ext/amrnb/: Core already took the lock.

ext/amrnb/: Core already took the lock.

Original commit message from CVS:
* ext/amrnb/amrnbdec.c: (gst_amrnbdec_init), (gst_amrnbdec_chain),
(gst_amrnbdec_state_change):
* ext/amrnb/amrnbenc.c: (gst_amrnbenc_base_init),
(gst_amrnbenc_finalize), (gst_amrnbenc_chain),
(gst_amrnbenc_state_change):
* ext/amrnb/amrnbparse.c: (gst_amrnbparse_init),
(gst_amrnbparse_query), (gst_amrnbparse_chain),
(gst_amrnbparse_read_header), (gst_amrnbparse_loop),
(gst_amrnbparse_sink_activate), (gst_amrnbparse_state_change):
Core already took the lock.