The rtc-omap driver currently assumes that the rtc's
registers are at a fixed address and already mapped
into virtual memory space.  Remove those assumptions
so the same driver can be used for similar devices
that reside at different physical addresses (e.g.,
TI's DA8xx/OMAP-L13x SoC's).

Also allow the possibility for the timer and alarm
interrupts to use the same IRQ.
Signed-off-by: Mark A. Greer <mgreer@mvista.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Acked-by: Tony Lindgren <tony@atomide.com>