ARM: OMAP2+: Remove legacy support for zoom platforms

We now have pretty decent device tree based support for
zoom platforms. It's not complete, but basics work for
me so adding more features should be quite trivial.

Looks like also 3630 sdp is zoom based, and looking
at it's board file should also be trivial to support
with the device tree based booting.

Patches are welcome if people are still using these.

Signed-off-by: Tony Lindgren <tony@atomide.com>