ALSA: hda - Support rereading widgets under the function group

A codec may allow software to hide some unused pin/cvt widgets.

Sometimes BIOS does not enable the hidden widgets properly although they are
needed for the board. Thus the driver need to enable them as a board-specific
fixup and the whole tree will change.

This patch implements a common code for rereading codec widgets. So the fixup
code can call it after enabling the hidden widgets.

Signed-off-by: Mengdong Lin <mengdong.lin@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>