rtc: omap: drop vendor-prefix from power-controller dt property

Drop the vendor-prefix from the "ti,system-power-controller" device-tree
property name.

It has been agreed to make "system-power-controller" a standard property
and to drop the vendor-prefix that is currently used by several drivers.

Note that drivers that have used "<vendor>,system-power-controller" in a
released kernel will need to support both versions.

Signed-off-by: Johan Hovold <johan@kernel.org>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Benot Cousson <bcousson@baylibre.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Felipe Balbi <balbi@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>