davinci: da850: add support for SATA interface

Add support for SATA controller on the
DA850/OMAP-L138/AM18x devices.

The patch adds the necessary clocks, platform
resources and a routine to initialize the SATA
controller.

The PHY configuration in this patch is
courtesy the work done by Zegeye Alemu,
Swaminathan and Mansoor Ahamed from TI.

While testing this patch, enable port multiplier
support iff you are actually using one. The
reasons of this behaviour are discussed
here: http://patchwork.ozlabs.org/patch/78163/



ChangeLog:
v3:
Removed fields which were being initialized
to zero in PHY configuration. Moved SATA base
address definition to the top of the file to
make it inline with what is done for the rest
of the modules.
v2:
Addressed comments from Sergei. Removed unnecessary
braces and removed unnecessary else after goto.

Signed-off-by: Sekhar Nori <nsekhar@ti.com>