OMAP4: PM: Use the low-power state change feature on OMAP4

For pwrdm's which support LOWPOWERSTATECHANGE, do not try waking
up the domain to put it back to deeper sleep state.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Benoit Cousson <b-cousson@ti.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>