ia64: mmap: Consider pgoff when searching for free mapping

IA64 is the only architecture which does not consider the pgoff value when
searching for a possible free memory region with vm_unmapped_area().
Adding this seems to have no negative side effect on IA64, so add it now
to make IA64 consistent with all other architectures.

Cc: stable@vger.kernel.org # 6.4
Signed-off-by: Helge Deller <deller@gmx.de>
Tested-by: matoro <matoro_mailinglist_kernel@matoro.tk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-ia64@vger.kernel.org
Link: https://lore.kernel.org/r/20230721152432.196382-3-deller@gmx.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>