ALSA: hda - Add amp initialization for realtek auto mode

In the realtek auto-probing mode, the initialization of amp with
some magic COEF or EAPD verbs is applied only when the codec SSID
has valid values to satisfy the realtek's definition.
However, many devices don't provide in that way, thus the device
doesn't work as is.

This patch allows the same initialization code even if the SSID
doesn't pass the bit test.  Also, alc_subsystem_id() is changed
just to check and define the type, so that it's called in the
parser, instead of the initializer.

Signed-off-by: Takashi Iwai <tiwai@suse.de>