Add missing break statement in the function omap3xxx_check_revision.

The commit id 4390f5b2 [ARM: OMAP: TI814X: Add cpu type macros
and detection support], removed the 'break' statement from the function
omap3xxx_check_revision(), resulting into wrong omap/cpu_revision
initialization for AM335x devices.
Signed-off-by: NVaibhav Hiremath <hvaibhav@ti.com>
[tony@atomide.com: refreshed to apply after changes to cpu_rev]
Signed-off-by: NTony Lindgren <tony@atomide.com>