ALSA: hda/tas2781: configure the amp after firmware load

Make the amp available immediately after a module
load to avoid having to wait for a PCM hook action.
(eg. unloading & loading the module while listening
music)

Signed-off-by: Gergo Koteles <soyer@irl.hu>
Link: https://lore.kernel.org/r/7f2f65d9212aa16edd4db8725489ae59dbe74c66.1703895108.git.soyer@irl.hu
Signed-off-by: Takashi Iwai <tiwai@suse.de>