mb/google/skyrim: Fix eMMC reset GPIO

On Skyrim variants, the eMMC reset GPIO should be SSD_AUX_RST_L (GPIO6).
Update the port_descriptors to link the correct reset GPIO. Data
is from the skyrim variant schematics and go/skyrim-gpios.

BUG=b:278759559
TEST=reboot: 5 iterations
suspend_stress_test: 10 iterations

Signed-off-by: Jon Murphy <jpmurphy@google.com>
Change-Id: I4713b3af23bb7684c9e2e81cf9c8d8a560b41a79
Reviewed-on: https://review.coreboot.org/c/coreboot/+/74512
Reviewed-by: Tim Van Patten <timvp@google.com>
Reviewed-by: Matt DeVillier <matt.devillier@amd.corp-partner.google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martin.roth@amd.corp-partner.google.com>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>

src/mainboard/google/skyrim/variants/markarth/port_descriptors.c

@@ -35,7 +35,7 @@ static const fsp_dxio_descriptor emmc_dxio_descriptors[] = {
 		.link_aspm = ASPM_L1,
 		.link_aspm_L1_1 = true,
 		.link_aspm_L1_2 = true,
-		.gpio_group_id = GPIO_27,
+		.gpio_group_id = GPIO_6,
 		.clk_req = CLK_REQ1,
 	},
 };

src/mainboard/google/skyrim/variants/winterhold/port_descriptors.c

@@ -35,7 +35,7 @@ static const fsp_dxio_descriptor emmc_dxio_descriptors[] = {
 		.link_aspm = ASPM_L1,
 		.link_aspm_L1_1 = true,
 		.link_aspm_L1_2 = true,
-		.gpio_group_id = GPIO_27,
+		.gpio_group_id = GPIO_6,
 		.clk_req = CLK_REQ1,
 	},
 };