rockchip: Pinephone Pro: Add DDR RAM type config

Add the RAM_ROCKCHIP_LPDDR4 to fix the Pinephone Pro booting.
When the configs were updated in 26f92be07e2 it somehow broke
the PPP boot process so let's fix it.

Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
CC: Jagan Teki <jagan@edgeble.ai>
CC: Kever Yang <kever.yang@rock-chips.com>
diff --git a/configs/pinephone-pro-rk3399_defconfig b/configs/pinephone-pro-rk3399_defconfig
index 4edea88..e4a8bee 100644
--- a/configs/pinephone-pro-rk3399_defconfig
+++ b/configs/pinephone-pro-rk3399_defconfig
@@ -73,6 +73,7 @@
 CONFIG_REGULATOR_PWM=y
 CONFIG_REGULATOR_RK8XX=y
 CONFIG_PWM_ROCKCHIP=y
+CONFIG_RAM_ROCKCHIP_LPDDR4=y
 CONFIG_DM_RNG=y
 CONFIG_RNG_ROCKCHIP=y
 CONFIG_BAUDRATE=1500000