[ARM] omap: clks: call recalc after any rate change

This implements the remainder of:
  OMAP clock: move rate recalc, propagation code up to plat-omap/clock.c
from Paul Walmsley which is not covered by the previous:
  [ARM] omap: move clock propagation into core omap clock code
  [ARM] omap: remove unnecessary calls to propagate_rate()
  [ARM] omap: move propagate_rate() calls into generic omap clock code
commits.

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