drm/simpledrm: Use struct iosys_map consistently

commit 8e8953a2c5cf699fc0025008f1422e912b55c7b0 from
https://nv-tegra.nvidia.com/r/3rdparty/canonical/linux-jammy.git

 jetson_36.3

The majority of the driver already uses struct iosys_map to encapsulate
accesses to I/O remapped vs. system memory. Accesses via the screen base
pointer still use __iomem annotations, which can lead to inconsistencies
and conflicts with subsequent patches.

Convert the screen base to a struct iosys_map as well for consistency
and to avoid these issues.

Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230120173103.4002342-5-thierry.reding@gmail.com


(cherry picked from commit fa904b4c)
Change-Id: I835083ee6b638fb909a411620d80683184154969
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/3rdparty/canonical/linux-jammy/+/2985863


Reviewed-by: svcacv <svcacv@nvidia.com>
Reviewed-by: Jonathan Hunter <jonathanh@nvidia.com>
GVS: Gerrit_Virtual_Submit <buildbot_gerritrpt@nvidia.com>
Signed-off-by: Rajeshkumar Ramasamy <rajeshkumar.ramasamy@windriver.com>