rockchip: rk3288-firefly: Include sdmmc regulator in SPL

Add bootph props and enable related Kconfig options to include the sdmmc
regulator in SPL. Also enable SPL_DM_SEQ_ALIAS to ensure aliases is
handled correctly in SPL.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/arch/arm/dts/rk3288-firefly-u-boot.dtsi b/arch/arm/dts/rk3288-firefly-u-boot.dtsi
index 435a02a..f953f68 100644
--- a/arch/arm/dts/rk3288-firefly-u-boot.dtsi
+++ b/arch/arm/dts/rk3288-firefly-u-boot.dtsi
@@ -52,6 +52,7 @@
 
 &gpio7 {
 	/delete-property/ bootph-all;
+	bootph-pre-ram;
 };
 
 &pcfg_pull_none {
@@ -109,3 +110,7 @@
 	bootph-pre-sram;
 	bootph-pre-ram;
 };
+
+&vcc_sd {
+	bootph-pre-ram;
+};