camera: Fix vendor tag descriptor corruption during binder transaction

For 64 bit platforms, size_t is 64 bit. Section count was not initialized
correctly. Hence the upper 32 bit of sectionCount will be corrupted and
lower 32 bit will be updated by the binder transaction leading to crash.

Change-Id: I35a4a750a5dbd8e696d14851130f2daf73014c3e