sys/dev/disk/dm: Don't implement "status" as a subset of "table" [2/2]

sys/dev/disk/dm: Don't implement "status" as a subset of "table" [2/2]

struct dm_target's "char *(*status)(void *);"
handler should be "char *(*table)(void *);"
given that it now has "char *(*info)(void *);"
to be compatible with Linux dm behavior.

This breaks API compatibility with NetBSD's dm, but the
previous commit already broke compatibility with NetBSD,
in order to implement it right.