sunxi: H6: move LPDDR3 timing definition into separate file

Currently the H6 DRAM driver only supports one kind of LPDDR3 DRAM.
Split the timing parameters for this LPDDR3 configuration  into a
separate file, to allow selecting an alternative later at compile time
(as the sunxi-dw driver does).

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Jernej Skrabec <jernej.skrabec@siol.net>
Reviewed-by: Jernej Skrabec <jernej.skrabec@siol.net>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/configs/beelink_gs1_defconfig b/configs/beelink_gs1_defconfig
index f5de850..eec4edd 100644
--- a/configs/beelink_gs1_defconfig
+++ b/configs/beelink_gs1_defconfig
@@ -3,6 +3,7 @@
 CONFIG_NR_DRAM_BANKS=1
 CONFIG_SPL=y
 CONFIG_MACH_SUN50I_H6=y
+CONFIG_SUNXI_DRAM_H6_LPDDR3=y
 CONFIG_MMC0_CD_PIN="PF6"
 CONFIG_MMC_SUNXI_SLOT_EXTRA=2
 # CONFIG_PSCI_RESET is not set