OMAP2+: hwmod: Fix the HW reset management

The HW reset must be de-assert after the clocks are enabled
but before waiting for the target to be ready. Otherwise the
reset might not work properly since the clock is not running
to proceed the reset.

De-assert the reset after _enable_clocks and before
_wait_target_ready.
Re-assert it only when the clocks are disabled.

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