drm/xe/migrate: skip bounce buffer path on xe2

drm/xe/migrate: skip bounce buffer path on xe2

Now that we support MEM_COPY we should be able to use the PAGE_COPY
mode, otherwise falling back to BYTE_COPY mode when we have odd
sizing/alignment.

v2:
 - Use info.has_mem_copy_instr
 - Rebase on latest changes.
v3 (Matt Brost):
 - Allow various pitches including 1byte pitch for MEM_COPY

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/20251022163836.191405-8-matthew.auld@intel.com