sunxi: a133: dram: fix data type for address variable

sunxi: a133: dram: fix data type for address variable

Variables holding addresses are typically using the "long" C type in
U-Boot, to be easily compatible with both 32-bit and 64-bit builds.

The A133 DRAM driver is typically compiled for AArch64, so u64 is the
same type as unsigned long, but that breaks when compiling the DRAM
driver in AArch32 (for some experiments).

Fix the type to make the code more portable.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>