msm: camera: flash: Add support for i2c flash

Add Support for qup i2c based flash. Update i2c driver
probe function and added  init for gpio pin control
table. Since positive return values are not errors for
qup i2c rx and tx data transfer, fix the return type
for the APIs. Added check for null pointer in get flash
dt data for device node.

CRs-Fixed: 3056236
Change-Id: If33086c80bd7d5c1403aedf1a2c01867d6c56687
Signed-off-by: Vishal Verma <vishverm@codeaurora.org>