Revert "drm/panfrost: Use drm_gem_map_offset()"

This reverts commit 583bbf46133c726bae277e8f4e32bfba2a528c7f.

Turns out we need mmap to work on imported BOs even if the current code
is buggy.

Signed-off-by: Rob Herring <robh@kernel.org>
1 file changed