sunxi: add LPDDR3 DRAM type support for DesignWare-like DRAM controller

Some A64 boards (SoPine and Pinebook production batch) use LPDDR3 DRAM
chips.

Add support for LPDDR3 DRAM in the DesignWare-like DRAM controller code.

Real LPDDR3 chips' support is not added yet in this commit.

Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
Tested-by: Jagan Teki <jagan@amarulasolutions.com>

arch/arm/mach-sunxi/Kconfig

@@ -226,6 +226,9 @@ config SUNXI_DRAM_DDR3
 config SUNXI_DRAM_DDR2
 	bool
 
+config SUNXI_DRAM_LPDDR3
+	bool
+
 choice
 	prompt "DRAM Type and Timing"
 	default SUNXI_DRAM_DDR3_1333 if !MACH_SUN8I_V3S

arch/arm/mach-sunxi/dram_sunxi_dw.c

@@ -342,6 +342,8 @@ static void mctl_set_cr(uint16_t socid, struct dram_para *para)
 	       MCTL_CR_DDR3 | MCTL_CR_2T |
 #elif defined CONFIG_SUNXI_DRAM_DDR2
 	       MCTL_CR_DDR2 | MCTL_CR_2T |
+#elif defined CONFIG_SUNXI_DRAM_LPDDR3
+	       MCTL_CR_LPDDR3 | MCTL_CR_1T |
 #else
 #error Unsupported DRAM type!
 #endif