msm: mdss: Correct the condition check for AD input ioctl

One of the condition checks in ad_input ioctl is to check the input
mode is not MDSS_AD_CALIB_MODE. The current code missed one pair
of brackets and made the check invalid. Correct the check to fix
the bug.

Change-Id: I82a083fe8a1bef6c57a01e20e02fdd14f8c09bde
Signed-off-by: Ping Li <pingli@codeaurora.org>