commit 8c9e06e6 upstream.

Commit a0b5cd4a ("bus: mvebu-mbus: use automatic I/O
synchronization barriers") enabled the usage of automatic I/O
synchronization barriers by enabling bit WIN_CTRL_SYNCBARRIER in the
control registers of MBus windows, but on non io-coherent platforms
(orion5x, kirkwood and dove) the WIN_CTRL_SYNCBARRIER bit in
the window control register is either reserved (all windows except 6
and 7) or enables read-only protection (windows 6 and 7).
Signed-off-by: Nicolas Schichan <nschichan@freebox.fr>
Reviewed-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Fixes: a0b5cd4a ("bus: mvebu-mbus: use automatic I/O synchronization barriers")
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>