Add support for multiple subchannel sets. Works with arbitrary devices in
subchannel set 1 and is transparent to device drivers. Although currently
only two subchannel sets are available, this will work with the architectured
maximum number of subchannel sets as well.
Signed-off-by: Cornelia Huck
Signed-off-by: Martin Schwidefsky
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds