ARM: OMAP4: PM: Add dummy hooks for OMAP4 dpll api's

This patch adds dummy hooks for OMAP4 dpll api's. Removes
dummy hooks for clkdev api's and enables CLKDEV
for OMAP4.
Also comments clockdomain calls from within the clock
framework as its not supported yet for OMAP4.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Benoit Cousson <b-cousson@ti.com>