ALSA: firewire-lib: Rename functions, structure, member for AMDTP

This patch renames some functions, a structure and its member to reuse them
in both AMDTP in/out stream.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --cc sound/firewire/amdtp.c
Simple merge

diff --cc sound/firewire/amdtp.h
Simple merge

diff --cc sound/firewire/dice.c
Simple merge

diff --cc sound/firewire/speakers.c
Simple merge