defconfig: msm8916: enable NCP6335D and FAN53555 regulator drivers

MSM8939 uses external I2C controlled buck regulator to supply APC power
rail. Enable Onsemi NCP6335D and Fairchild FAN53555 regulator drivers to
support both on MSM8939 boards.

Change-Id: I26e40cd950e98ede16a2ce2beb663861936731fe
Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org>