OMAP clock: support "dry run" rate and parent changes

OMAP clock: support "dry run" rate and parent changes

For upcoming notifier support, modify the rate recalculation code to
take parent rate and rate storage parameters.  The goal here is to
allow the clock code to determine what the clock's rate would be after
a parent change or a rate change, without actually changing the
hardware registers.  This is used by the upcoming notifier patches to
pass a clock's current and planned rates to the notifier callbacks.

Also add a new clock flag, RECALC_ON_ENABLE, which causes the clock
framework code to recalculate the current clock's rate and propagate
down the tree after a clk_enable() or clk_disable().  This is used by
the OMAP3 DPLLs, which change rates when they enable or disable, unlike
most clocks.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>