[ARM] 5302/1: ARM: OMAP: Revert omap3 WDT changes to avoid merge conflict

With the upcoming WDT patches OMAP_WDT_BASE is no longer needed
in devices.c. Revert some earlier omap3 changes to avoid merge
conflicts with the WDT patches.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>