ram: rockchip: Add common ddr type configs

We have common ddr types in rockchip or in general. So use
the common ddr type names instead of per Rockchip SoC to
avoid confusion.

The respective ddr type names will use on the associated
ddr SoC driver as these drivers are built per SoC at a time.

Signed-off-by: Jagan Teki <jagan@edgeble.ai>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/configs/roc-pc-mezzanine-rk3399_defconfig b/configs/roc-pc-mezzanine-rk3399_defconfig
index e800110..00239c2 100644
--- a/configs/roc-pc-mezzanine-rk3399_defconfig
+++ b/configs/roc-pc-mezzanine-rk3399_defconfig
@@ -69,7 +69,7 @@
 CONFIG_REGULATOR_RK8XX=y
 CONFIG_PWM_ROCKCHIP=y
 # CONFIG_RAM_ROCKCHIP_DEBUG is not set
-CONFIG_RAM_RK3399_LPDDR4=y
+CONFIG_RAM_ROCKCHIP_LPDDR4=y
 CONFIG_DM_RESET=y
 CONFIG_BAUDRATE=1500000
 CONFIG_DEBUG_UART_SHIFT=2