MAINTAINERS: update s-Par driver maintainer list

Benjamin Romer is no longer a maintainer for the Unisys s-Par driver,
presently in drivers/staging/unisys/.

Signed-off-by: David Kershner <david.kershner@unisys.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>