Instead of "open coding" a DEVICE_ATTR() define, use the
DEVICE_ATTR_WO() macro instead, which does everything properly instead.

This does require a few static functions to be renamed to work properly,
but thanks to a script from Joe Perches, this was easily done.
Reported-by: Joe Perches <joe@perches.com>
Cc: Peter Chen <Peter.Chen@nxp.com>
Cc: Valentina Manea <valentina.manea.m@gmail.com>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: Johan Hovold <johan@kernel.org>
Acked-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>