add core.c, clock.c, and clock.h in mach-bcmring

implement timer init, clocksource init, amba device init
implement clock set/get enable/disable API
add dummy clkdev.h
Signed-off-by: NLeo Chen <leochen@broadcom.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

People often point to the Integrator/Versatile/Realview
implementations to justify using the consumer name as the sole
selector for clocks.

Eliminate this excuse by changing the Realview implementation, so
it provides a better example of how it should be done.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>