power: isl9519q: start/stop charging during suspend

If the i2c bus is suspend and msm_charger asks the isl charger
to start or stop charging, the isl charger immediately accesses
the i2c bus to program the isl chip. These i2c transactions
causes failures when i2c is suspended.

Remember the suspended state of the device (and hence the i2c bus),
and if a transaction is desired while it is suspended, execute
them when the isl device resumes.

Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>