drm/msm/mdp5: Fix negative SMP block allocation
drm/msm/mdp5: Fix negative SMP block allocation

In case we request a number of SMP blocks which is lower than
the already reserved blocks, we should not try to allocate a
negative number, but 0 blocks instead.

Signed-off-by: Stephane Viau <d4fda244ee25abe7d0b7d782a99f7543e6ef436b@codeaurora.org>
Signed-off-by: Rob Clark <915c10c999604870200b6defbe633d857c856ca0@gmail.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs