ARM: OMAP1: Move SoC specific headers from plat to mach for omap1

There's no need to have these in plat-omap any longer. Note that these
could eventually be made local to mach-omap1 instead of being in mach.

But to do that, at least various driver access using omap7xxx.h registers
needs to be fixed first.

Cc: spi-devel-general@lists.sourceforge.net
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Tony Lindgren <tony@atomide.com>