commit f8a06977 upstream.

Don't allow everybody to change device hardware registers.

Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>