Change in coreboot[master]: mb/google/dedede/var/blipper: Update devicetree and gpio setting

[Ben Kao (Code Review)]

Attention is currently required from: zanxi chen, Karthik Ramasubramanian.
Ben Kao has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/55385 )

Change subject: mb/google/dedede/var/blipper: Update devicetree and gpio setting
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Patch Set 1:

(5 comments)

File src/mainboard/google/dedede/variants/blipper/gpio.c:

https://review.coreboot.org/c/coreboot/+/55385/comment/1da50e92_4008ffa6 
PS1, Line 9: static const struct pad_config gpio_table[] = {
1. if no WWAN, we can set WWAN related pins to NC.
2. if UART2_RTS_N and UART2_CTS_N are unused, please set it to NC.
3. if AP_I2C_EMR_SCL and AP_I2C_EMR_SDA are unused, please set it to NC.
4. if GPP_E0 is unused, please set it to NC.

https://review.coreboot.org/c/coreboot/+/55385/comment/5cac5239_e4456299 
PS1, Line 22: /* G7  : SD_SDIO_WP */
            : 	PAD_NC(GPP_G7, NONE),
if GPP_G7 is set to NC, it will have SD card detection issue, please remove it.

File src/mainboard/google/dedede/variants/blipper/overridetree.cb:

https://review.coreboot.org/c/coreboot/+/55385/comment/c0023f4f_41575ea5 
PS1, Line 25: 		.i2c[1] = {
            : 			.speed = I2C_SPEED_FAST,
            : 		},
You can remove it if you don't use it anymore.

https://review.coreboot.org/c/coreboot/+/55385/comment/ea64e12b_91bf16b1 
PS1, Line 31: 		.i2c[3] = {
            : 			.speed = I2C_SPEED_FAST,
            : 		},
You can remove it if you don't use it anymore.

https://review.coreboot.org/c/coreboot/+/55385/comment/0a03aacd_8c25aa1e 
PS1, Line 61: register "enable_gpio" = "ACPI_GPIO_OUTPUT_ACTIVE_HIGH(GPP_D13)"
What's the purpose? It may delay the enabling of the USB camera during system startup, you can remove it and observe the enabling time of USB camera.