sunxi: add sun7i clocks and timer support.

sunxi: add sun7i clocks and timer support.

This patch adds the basic clocks and timer support for the Allwinner A20
(sun7i) processor. This code will not been compiled until the build is hooked
up in a later patch. It has been split out to keep the patches manageable.

Some of the code here is common to multiple sunxi subarchtectures, hence files
are named sun4i which is the earliest similar variant.

Signed-off-by: Alexandru Gagniuc <[email protected]>
Signed-off-by: Chen-Yu Tsai <[email protected]>
Signed-off-by: Emilio López <[email protected]>
Signed-off-by: Hans de Goede <[email protected]>
Signed-off-by: Henrik Nordstrom <[email protected]>
Signed-off-by: Jens Kuske <[email protected]>
Signed-off-by: Luke Leighton <[email protected]>
Signed-off-by: Oliver Schinagl <[email protected]>
Signed-off-by: Ian Campbell <[email protected]>
Cc: Stefan Roese <[email protected]>
Cc: Tom Cubie <[email protected]>
Reviewed-by: Tom Rini <[email protected]>