drivers: soc: sunxi: Add support for the C1 SRAM region

This introduces support for the SRAM C1 section, that is controlled by
the system controller. This SRAM area can be muxed either to the CPU
or the Video Engine, that needs this area to store various tables (e.g.
the Huffman VLD decoding tables).

This only supports devices with the same layout as the A10 (which also
includes the A13, A20, A33 and other SoCs).

Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>