fs/procfs: improve PROCMAP_QUERY's compat mode handling

Kernel provides compat_ptr_ioctl() wrapper to sanitize pointers for 32-bit
processes on 64-bit host architectures.  Given procfs_procmap_ioctl()
always expects pointer argument, this is exactly what we need.

This has any effect only on 32-bit processes on s390 architecture.

Link: https://lkml.kernel.org/r/20240701174805.1897344-2-andrii@kernel.org


Fixes: 3757be49 ("fs/procfs: implement efficient VMA querying API for /proc/<pid>/maps")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>