msm: mdss: Validate input argument

MDP kernel function allocates memory using one of the input
parameters. Add sanity check for this input parameter to
ensure proper memory allocation.

Change-Id: Ib7ff3b02e818c0d2a623fb3428fb93cc5bd8e41e
Signed-off-by: Shalabh Jain <shalabhj@codeaurora.org>
msm: mdss: Prevent ALS data configuration when AD is disabled

If assertive display is disabled, backlight data structure is reset
to NULL, which in some conditons gets dereferenced or casuses
crash.

Change-Id: I535eac6d2f0aef222fc2846f80d72db1f3e3480d
Signed-off-by: Ping Li <quicpingli@codeaurora.org>