i2c_qup: Improve implementation of PM callbacks

Refactor PM callbacks and remove redundant variable.
Add support for configuration of clockcontrol event.
Now the clock's state may be set by pm calls (as before)
or by a transfer's begining and ending.
Runtime-PM is still used in autosuspend configuration for
expensive NoC voting/unvoting since that may go to remote
processor.

CRs-Fixed: 592435
Change-Id: I54f7c67f768336f66765a04006b4c8e4734ac277
Signed-off-by: Gilad Avidov <gavidov@codeaurora.org>
Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
Signed-off-by: Sana Venkat Raju <c_vsana@codeaurora.org>

Conflicts:
	Documentation/devicetree/bindings/i2c/i2c-qup.txt