ARM: OMAP2+: SoC name and revision unification

This is a long story where for each new generation of
OMAP we used different approaches for creating
strings for SoCs names and revisions that this patch
fixes. It makes future exporting of this information
to SoC infrastructure easier.

Signed-off-by: Ruslan Bilovol <ruslan.bilovol@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>