google/snappy: Update EC keyboard backlight flag by SKU ID

Set AP SKU ID by ec command EC_CMD_SET_SKU_ID to update EC keyboard backlight
flag.

BUG=b:65359225
BRANCH=reef
TEST=emerge-snappy coreboot
Change-Id: I1153aa0b89250c55f311dd93a01fcef47afd7292
Signed-off-by: Kevin Chiu <Kevin.Chiu@quantatw.com>
Reviewed-on: https://review.coreboot.org/21400
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/mainboard/google/reef/mainboard.c

@@ -42,6 +42,8 @@ static void mainboard_init(void *chip_info)
 	gpio_configure_pads(pads, num);
 
 	mainboard_ec_init();
+
+	variant_board_ec_set_skuid();
 }
 
 /*
@@ -64,6 +66,11 @@ uint8_t __attribute__((weak)) variant_board_sku(void)
 	return board_sku_num;
 }
 
+/* Set variabnt board sku to ec by sku id */
+void __attribute__((weak)) variant_board_ec_set_skuid(void)
+{
+}
+
 const char *smbios_mainboard_sku(void)
 {
 	static char sku_str[7]; /* sku{0..255} */