drm/xe/migrate: fix copy direction in access_memory
After we do the modification on the host side, ensure we write the
result back to VRAM and not the other way around, otherwise the
modification will be lost if treated like a read.
Fixes:
270172f64b11 ("drm/xe: Update xe_ttm_access_memory to use GPU for non-visible access")
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://lore.kernel.org/r/20250710134128.800756-2-matthew.auld@intel.com
(cherry picked from commit
c12fe703cab93f9d8bfe0ff32b58e7b1fd52be1f)
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>