msm: mdss: Returning generic error code on overlay scaling hw limitation

Added appropriate error code for hardware limitation on mdp overlay
vertical scaling. On encountering the error, it is expected to ignore
the error and fallback to GPU.

Change-Id: Ib3a7767a856ed4d80632aabd7e371d2766b53dc1
Signed-off-by: Veera Sundaram Sankaran <veeras@codeaurora.org>