HDA-Intel: present up to 8 HDMI/DP outputs via "hdmi" device

HDA-Intel: present up to 8 HDMI/DP outputs via "hdmi" device

Some new AMD cards have HDA codecs presenting 6 connected HDMI/DP pin
nodes (plus 1 unconnected pin node) according to the ALSA card database.

Example:
http://www.alsa-project.org/db/?f=de3ced7af41de0ed54d218650e5e2f16c511787b

Bump the maximum number of presented HDMI outputs per card via the
"hdmi" PCM from 4 to 8 (so that the last possible device is DEV=7).

Note that HDMI PCM devices DEV=4..7 use shared PCM device numbers, so
HDA cards that have over 4 audio PCM devices or multiple S/PDIF or modem
devices will have their remaining PCM devices misrepresented as HDMI
devices.

Signed-off-by: Anssi Hannula <anssi.hannula@iki.fi>
Signed-off-by: Takashi Iwai <tiwai@suse.de>