msm: camera: Check IOCTL input data for NULL pointer

The argument of the IOCTL function is checked for NULL, but
the pointer that is used to get the data is not checked. This may
cause NULL pointer dereferencing.

Change-Id: I2c732cf9f0d26095685f2119fb60ddb74298ffb9
Signed-off-by: Iliya Varadzhakov <ivarad@codeaurora.org>
Signed-off-by: Hody Hung <hhung@codeaurora.org>