Update xe_migrate_doc.h with 32 page table structs (not 48)

v2: minor typo fix
Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/20230306133459.7803-1-niranjana.vishwanathapura@intel.comSigned-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>