This patch adds extra functions for shutdown on the Sound Blaster Z and
Recon3Di. The Recon3Di only has one specific functions, which sets the
GPIO data pins to 0 to prevent a popping noise.

The Sound Blaster Z exit sequence was taken from Windows. Without this
exit function, the card will not reload properly unless the PC has been
shutdown to clear the onboard memory. There are commented out functions
currently in the sbz_exit_chip function that are added in a later patch.

Also, a reboot notify function has been added, to make sure these
functions are ran before a reboot. This helps when using the card
through VFIO in a virtual machine, to make sure the card reloads the DSP
properly.
Signed-off-by: Connor McAdams <conmanx360@gmail.com>
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>