ALSA: ymfpci: Store saved legacy registers in an array

In preparation for storing more than two legacy PCI registers, the
existing ones are moved into a new array.

Signed-off-by: Tasos Sahanidis <tasos@tasossah.com>
Link: https://lore.kernel.org/r/20230329041440.177363-4-tasos@tasossah.com


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