Change in coreboot[master]: mb/google/skyrim: Configure SD card reader power sequence

[Raul Rangel (Code Review)]

Attention is currently required from: Ian Feng, Eric Lai, Karthik Ramasubramanian.
Raul Rangel has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/63739 )

Change subject: mb/google/skyrim: Configure SD card reader power sequence
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Patch Set 5:

(3 comments)

File src/mainboard/google/skyrim/variants/baseboard/gpio.c:

https://review.coreboot.org/c/coreboot/+/63739/comment/e4dd9ffc_75d70427 
PS5, Line 189: 	/* SD_AUX_RESET_L  */
             : 	PAD_GPO(GPIO_27, LOW),
I think this pin will always get reset, so no need to add it here.

https://review.coreboot.org/c/coreboot/+/63739/comment/aa841415_843acef1 
PS5, Line 201: PAD_GPO
Can you try the following: `PAD_NFO(GPIO_27, PCIE_RST1_L, HIGH),` also update it in the ramstage list.

https://review.coreboot.org/c/coreboot/+/63739/comment/b231c1e3_86a72cb7 
PS5, Line 201: 	PAD_GPO(GPIO_27, HIGH),
> Yes,remove set HIGH SD card is not working.

I suspect it's a timing issue. How long does the SD controller need after reset is de-asserted before it can be enumerated?