staging: unisys: memregion: Embed memregion in struct channel

This changes the API for visor_memregion_create() to require a
pre-allocated struct memregion. Embedding this in struct channel
avoids a layer of additional kmalloc()'s and error checks.

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>