drm/msm/adreno: Ensure that the zap shader region is big enough

Before loading the zap shader we should ensure that the reserved memory
region is big enough to hold the loaded file.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Jeffrey Hugo <jeffrey.l.hugo@gmail.com>
Signed-off-by: Rob Clark <robdclark@chromium.org>