ARM: dts: OMAP5 / DRA7: switch over to interrupts-extended property for UART

We've had deeper idle states working on omaps for few years now,
but only in the legacy mode. When booted with device tree, the
wake-up events did not have a chance to work until commit
3e6cee17 ("pinctrl: single: Add support for wake-up interrupts")
that recently got merged. In addition to that we also needed
commit 79d97015 ("of/irq: create interrupts-extended property")
that's now also merged.

Note that there's no longer need to specify the wake-up bit in
the pinctrl settings, the request_irq on the wake-up pin takes
care of that.

Signed-off-by: Nishanth Menon <nm@ti.com>