Earlier, the hwmod code had considered the OCP_SYSCONFIG.CLOCKACTIVITY
bits to be incremental power saving bits, controlling internal IP
block clock gates.  This was a misapprehension.  The CLOCKACTIVITY
bits are used to indicate, in advance, which clocks will be cut when
the module acknowledges an idle request.  This enables the IP block to
take whatever action is necessary to complete any in-progress work
before asserting its IdleAck.

In the current Linux-OMAP code, this implies that the clock framework
should be changing module CLOCKACTIVITY bits as module clocks are enabled
and disabled.  We don't do that yet, but in the future, we should.
This must wait until the clock tree is annotated with omap_hwmod pointers
(or vice-versa).  In the meantime, drop most of the hwmod code that
controls CLOCKACTIVITY bits to avoid confusion.

This patch has benefited from many illuminating discussions with (in
alphabetical order) Benoît Cousson <b-cousson@ti.com>, Rajendra Nayak
<rnayak@ti.com>, and Sebastien Sabatier <s-sabatier1@ti.com>.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Rajendra Nayak <rnayak@ti.com>
Cc: Sebastien Sabatier <s-sabatier1@ti.com>
Cc: Benoît Cousson <b-cousson@ti.com>