ARM: OMAP: remove unused cpu detection macros

Now that OMAP730 and OMAP850 support is mostly unified, there's no
need for separate cpu detection macros for these architectures. At
least, currently there isn't, because both macros are unused.
cpu_is_7xx() seems to cover all possible uses.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
[tony@atomide.com: updated to also to remove related IS_OMAP_TYPE]
Signed-off-by: Tony Lindgren <tony@atomide.com>