soc/intel/alderlake: Enable eMMC based on dev enabled

1. Add eMMC device function in pci_devs.h.
2. Enable eMMC device and configuration based on dev enabled.
3. Add SOC acpi name for eMMC.

Change-Id: I44f17420f7a2a1ca0fbb6cfb1886b1617c5a5064
Signed-off-by: Krishna Prasad Bhat <krishna.p.bhat.d@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/61129
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Rizwan Qureshi <rizwan.qureshi@intel.com>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>

src/soc/intel/alderlake/chip.h

@@ -419,6 +419,11 @@ struct soc_intel_alderlake_config {
 	 * accordingly */
 	uint8_t HybridStorageMode;
 
+#if CONFIG(SOC_INTEL_ALDERLAKE_PCH_N)
+	/* eMMC HS400 mode */
+	uint8_t emmc_enable_hs400_mode;
+#endif
+
 	/*
 	 * Override CPU flex ratio value:
 	 * CPU ratio value controls the maximum processor non-turbo ratio.