msm: camera: Adopt camera drivers to use generic api to get v4l2 fops

Adopt all camera drivers to use generic api to get v4l2 fops
instead of directly referring the global variable in v4l2
framework.

Change-Id: I2c73c4d5354bb1ee571b265c2668c36617b66f9a
Signed-off-by: Hariram Purushothaman <hariramp@codeaurora.org>