mm/mprotect: replace can_modify_mm with can_modify_vma

Avoid taking an extra trip down the mmap tree by checking the vmas
directly.  mprotect (per POSIX) tolerates partial failure.

Link: https://lkml.kernel.org/r/20240817-mseal-depessimize-v3-3-d8d2e037df30@gmail.com


Signed-off-by: Pedro Falcato <pedro.falcato@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>