mb/google/hatch: Add support for variant_memory_sku()

This change adds support for variant_memory_sku() that allows variant
to return memory SKU ID. Current implementation of memory_sku() is
renamed to weak implementation of variant_memory_sku(). Functionally
this change should be the same as before for all hatch variants. This
function will be overriden by helios in a follow-up CL.

BUG=b:133455595

Change-Id: I509c263ec08e0060c12ef1ea9fed673f1e3f3a41
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34251
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Fagerburg <pfagerburg@chromium.org>

src/mainboard/google/hatch/romstage.c

@@ -29,7 +29,7 @@
  */
 #define GPIO_MEM_CH_SEL		GPP_F2
 
-static int memory_sku(void)
+int __weak variant_memory_sku(void)
 {
 	const gpio_t spd_gpios[] = {
 		GPIO_MEM_CONFIG_0,
@@ -48,7 +48,7 @@ void mainboard_memory_init_params(FSPM_UPD *memupd)
 	int is_single_ch_mem;
 
 	variant_memory_params(&memcfg);
-	mem_sku = memory_sku();
+	mem_sku = variant_memory_sku();
 	/*
 	 * GPP_F2 is the MEM_CH_SEL gpio, which is set to 1 for single
 	 * channel skus and 0 for dual channel skus.

src/mainboard/google/hatch/variants/baseboard/include/baseboard/variants.h

@@ -34,6 +34,9 @@ const struct pad_config *override_early_gpio_table(size_t *num);
 /* Return board specific memory configuration */
 void variant_memory_params(struct cnl_mb_cfg *bcfg);
 
+/* Return memory SKU for the variant */
+int variant_memory_sku(void);
+
 /* Return variant specific gpio pads to be configured during sleep */
 const struct pad_config *variant_sleep_gpio_table(u8 slp_typ, size_t *num);