rockchip: rk3288: pinctrl: Fix HDMI pinctrl

Since the device tree does not specify the EDID pinctrl option for HDMI we
must set it manually. Fix the driver to handle this.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/pinctrl/rockchip/pinctrl_rk3288.c b/drivers/pinctrl/rockchip/pinctrl_rk3288.c
index 8356786..7c769bd 100644
--- a/drivers/pinctrl/rockchip/pinctrl_rk3288.c
+++ b/drivers/pinctrl/rockchip/pinctrl_rk3288.c
@@ -503,6 +503,8 @@
 		return PERIPH_ID_I2C4;
 	case 65:
 		return PERIPH_ID_I2C5;
+	case 103:
+		return PERIPH_ID_HDMI;
 	}
 
 	return -ENOENT;