OMAP2+: clockdomain: Add 2 APIs to control clockdomain from hwmod framework

Duplicate the existing API for clockdomain enable from clock to enable
a clock domain from hwmod framework.
This will be needed when the hwmod framework will move from the current
clock centric approach to the module based approach.

These APIs are returning 0 for the moment for OMAP2 and OMAP3 until
their hwmods are updated with the clksm attribute.

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