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 <mr.nuke.me@gmail.com>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Emilio López <emilio@elopez.com.ar>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Henrik Nordstrom <henrik@henriknordstrom.net>
Signed-off-by: Jens Kuske <jenskuske@gmail.com>
Signed-off-by: Luke Leighton <lkcl@lkcl.net>
Signed-off-by: Oliver Schinagl <oliver@schinagl.nl>
Signed-off-by: Ian Campbell <ijc@hellion.org.uk>
Cc: Stefan Roese <sr@denx.de>
Cc: Tom Cubie <Mr.hipboi@gmail.com>
Reviewed-by: Tom Rini <trini@ti.com>