OMAP: Fix incorrect 730 vs 850 detection

Commit ae302f40 introduced support for omap850 but had a bug in
ifdef handling of the non-multi-omap case for 730 and 850.

Fix the problem by removing the non-multi-omap special handling,
as we need to detect between omap730 and omap850 anyways.

Problem reported by Sanjeev Premi <premi@ti.com>.

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