sunxi: H3: add DRAM controller single bit delay support

sunxi: H3: add DRAM controller single bit delay support

So far the DRAM driver for the H3 SoC (and apparently boot0/libdram as
well) only applied coarse delay line settings, with one delay value for
all the data lines in each byte lane and one value for the control lines.

Instead of setting the delays for whole bytes only allow setting it for
each individual bit. Also add support for address/command lane delays.

For the purpose of this patch the rules for the existing coarse settings
were just applied to the new scheme, so the actual register writes don't
change for the H3. Other SoCs will utilize this feature later properly.

With a stock GCC 5.3.0 this increases the dram_sun8i_h3.o code size from
2296 to 2344 Bytes.

[Andre: move delay parameters into macros to ease later sharing, use
	defines for numbers of delay registers, extend commit message]

Signed-off-by: Jens Kuske <jenskuske@gmail.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>