rtc: omap: let device wakeup capability be configured from chip init logic

The rtc-omap driver currently hardcodes the RTC wakeup capability to be
"not capable".  While this seems to be true for existing OMAP1 boards
which are not wired for this, the DA850/OMAP-L138 SoC, the RTC can always
be wake up source from its "deep sleep" mode.

This patch lets the wakeup capability be set from platform data and does
not override the setting from the driver.  For DA850/OMAP-L138, this is
done from arch/arm/mach-davinci/devices-da8xx.c:da8xx_register_rtc()

Note that this patch does not change the behavior on any existing OMAP1
board since the platform device registration sets the wakeup capability to
0 by default.

Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>