drm/msm/gem: Drop PAGE_SHIFT for address space mm

Get rid of all the unnecessary conversion between address/size and page
offsets.  It just confuses things.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20220411215849.297838-6-robdclark@gmail.com


Signed-off-by: Rob Clark <robdclark@chromium.org>