msm: mdss: update error codes returned to user space

Some of the error codes reported to user space may not be properly
handled or can be confused. Replacing the error codes returned with more
unique ones to correctly identify problem.

CRs-Fixed: 549702
Change-Id: I01ffff79e748fc852898dc7605fd15873dfb33f8
Signed-off-by: Adrian Salido-Moreno <adrianm@codeaurora.org>