drm/v3d: Move part of copying of reset/copy performance extension to a helper

The loop which looks up the syncobj and copies the kperfmon ids is
identical so lets move it to a helper.

The only change is replacing copy_from_user with get_user when copying a
scalar.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Reviewed-by: Maíra Canal <mcanal@igalia.com>
Signed-off-by: Maíra Canal <mcanal@igalia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240711135340.84617-7-tursulin@igalia.com