Amlogic broadcast timer

A meson SoC timer used for broadcast.

Required properties:

- compatible : should be "amlogic,bc-timer".
- reg : register of the timer
- timer_name : name of the meson timer used for broadcast.
- clockevent-rating : variable to rate clock event devices
- clockevent-shift : nanoseconds to cycles divisor (power of two)
- clockevent-features :  features, should be CLOCK_EVT_FEAT_PERIODIC(0x1) |
                         CLOCK_EVT_FEAT_ONESHOT(0x2) |
			 CLOCK_EVT_FEAT_DYNIRQ(0x20).
- interrupts : interrupt of the timer
- bit_enable : enable bit of control register
- bit_mode : mode bit of control register
- bit_resolution : resolution bit of control register

Example:

timer_bc {
	compatible = "amloigc,bc-timer";
	reg =   <0xffd0f190 0x8>;
	timer_name = "Meson TimerF";
	clockevent-rating=<300>;
	clockevent-shift=<20>;
	clockevent-features=<0x23>;
	interrupts = <0 60 1>;
	bit_enable=<16>;
	bit_mode=<12>;
	bit_resolution=<0>;
};