[ALSA] hda-intel - Show the last command in warning messages

Show the last issued command in warning messages when any communication
error with CORB/RIRB occurs.
Also, a bit code clean-up for composing the command value in
*_send_cmd().

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>