google/gru: Add support for rainier

Rainier is a scarlet-derived board but uses eDP as opposed to MIPI. Using
GRU_BASEBOARD_SCARLET is enough, except for display related logic. In
those cases, use board specific logic instead of baseboard. 


Change-Id: I596f7ca6bc26312ecaeb261c96cebd46974c2cdf
Signed-off-by: Ege Mihmanli <egemih@google.com>
Reviewed-on: https://review.coreboot.org/22542
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
diff --git a/src/mainboard/google/gru/mainboard.c b/src/mainboard/google/gru/mainboard.c
index 99b335a..076cfa1 100644
--- a/src/mainboard/google/gru/mainboard.c
+++ b/src/mainboard/google/gru/mainboard.c
@@ -237,7 +237,11 @@
 
 static void configure_display(void)
 {
-	if (IS_ENABLED(CONFIG_GRU_BASEBOARD_SCARLET)) {
+	/*
+	 * Rainier is Scarlet-derived, but uses EDP so use board-specific
+	 * config rather than baseboard.
+	 */
+	if (IS_ENABLED(CONFIG_BOARD_GOOGLE_SCARLET)) {
 		gpio_output(GPIO(4, D, 1), 0);	/* DISPLAY_RST_L */
 		gpio_output(GPIO(4, D, 3), 1);	/* PPVARP_LCD */
 		mdelay(10);