OMAP3/4: DPLL: Add allow_idle/deny_idle support for all DPLL's

All OMAP3/4 dpll's support hardware level autogating.
Populate allow_idle/deny_idle function pointers for all
DPLL's in clkops.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>