Support sysfs changes in the Linux 5.15 kernel.

DM_DEV_CREATE no longer creates sysfs nodes. Note this in ueventd and
add some helper APIs to libdm, so devices can be created with a
placeholder table.

This also fixes a bug in dmctl where the detailed info on suspended
devices was wrong.

Bug: 259328366
Test: dmctl with "uevents" tool
Change-Id: I822f8010e48d32841aa0ee508822f76d03a3dd85