ARM: OMAP2+: Add dm816x hwmod support

ARM: OMAP2+: Add dm816x hwmod support

Add minimal hwmod support that works at least on dm8168. This
is based on the code in the earlier TI CDP tree, and an earlier
patch by Aida Mynzhasova <aida.mynzhasova@skitlab.ru>.

I've set up things to work pretty much the same way as for
am33xx. We are basically using cm33xx.c with a different set
of clocks and clockdomains.

This code is based on the TI81XX-LINUX-PSP-04.04.00.02 patches
published at:

http://downloads.ti.com/dsps/dsps_public_sw/psp/LinuxPSP/TI81XX_04_04/04_04_00_02/index_FDS.html

Cc: Aida Mynzhasova <aida.mynzhasova@skitlab.ru>
Cc: Brian Hutchinson <b.hutchman@gmail.com>
Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>