UIO: fix UIO Kconfig dependencies

ae210f188614bb3d1ee3f19c64e28e3cdd44877c introduced a big "if UIO"/"endif"
where all uio drivers are defined.  So know there is no need for them to
depend explicitly on UIO.

Signed-off-by: Uwe Kleine-König <Uwe.Kleine-Koenig@digi.com>
Signed-off-by: Hans J. Koch <hjk@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>