[PATCH v2 00/07] enable devicetree on arch-mmp

Changelog
v2:
	* parse timer from DT
	* remove CONFIG_MMP_USE_OF
	* set NR_IRQS to 0 since sparse irq is enabled and allocated irq is started from NR_IRQS.
	* change property names according to comments
	* parse serial from DT and only use drivers/tty/serial/pxa.c. Avoid to touch drivers/tty/serial/of_serial.c