mm: remove unused macro INIT_PASID

mm: remove unused macro INIT_PASID

The macro INIT_PASID was originally used by mm_init_pasid.  However, since
commit a6cbd44093ef ("kernel/fork: Initialize mm's PASID"), mm_init_pasid
has been removed.  Therefore, INIT_PASID is no longer needed and is
removed.

Link: https://lkml.kernel.org/r/20250427145004.13049-1-hank20010209@gmail.com
Signed-off-by: Cheng-Han Wu <hank20010209@gmail.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>