input: synaptics: Secure touch clocks

Because of a change in the underlying bus driver, the secure
touch layer in the input drivers is now required to control
directly the clocks which are needed during the touch sessions.
Clocks are turned on/off when the session is started/ended.

Change-Id: Ib123ea6f9f38d990e1ab6e6bdbb776faeb591c11
Acked-by: Christian Bolis <cbolis@qti.qualcomm.com>
Signed-off-by: Keith Fallows <keithf@codeaurora.org>