[S] Change in coreboot[main]: mb/asus/p8z77-m: Support AC97 front audio panel

[Nicholas Chin (Code Review)]

Attention is currently required from: Keith Hui.

Nicholas Chin has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/79734?usp=email )

Change subject: mb/asus/p8z77-m: Support AC97 front audio panel
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Patch Set 2: Code-Review+1

(1 comment)

File src/mainboard/asus/p8x7x-series/variants/p8z77-m/hda_verb.c:

https://review.coreboot.org/c/coreboot/+/79734/comment/392de0e1_26b08335 :
PS2, Line 45: /*
            : 	 * The verbs above are for a HD Audio front panel.
            : 	 * With vendor firmware, if audio front panel type is set as AC97, line out 2
            : 	 * (0x1b) and mic 2 (0x19) pins of ALC887 are configured differently.
            : 	 *
            : 	 * The differences are all in the "Misc" fields of configuration defaults (in byte 2)
            : 	 * as shown below. ALC887 datasheet did not offer details on what those bits
            : 	 * (listed as reserved in HDA spec) are, so we'll have to take their word for it.
            : 	 *
            : 	 * Pin  | 0x19 | 0x1b
            : 	 * -----+------+-----
            : 	 * HDA  | 1100 | 1100
            : 	 * AC97 | 1001 | 0001
            : 	 */
I tried to see if there was anything in the Linux kernel that revealed what those reserved bits were being used for but couldn't find anything.