[ALSA] nm256: reset workaround for Latitude CSx

Modules: NM256 driver

The current snd-nm256 driver can cause Dell Latitude CSx laptops to
lock-up during module (un)load.  I have isolated this to the writes to
the control port register at offset 0x6cc which were not already
protected by the existing reset_workaround.

I tried grouping these writes with the existing reset_workaround
clause, but that caused the driver to have (un)load problems on the
Dell Latitude LS laptops.  So, I have implemented a reset_workaround_2
clause (please feel free to suggest a better name!) to cover this
situation and added a quirk entry for the CSx laptops.

Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>