Header has multiple constants defined using preprocessor
directive. In the cases where these are an integer progression an
enumeration type can be used. Doing so adds documentation to the code
and makes the usage explicit. Maintain original constant value, this
value is returned by the device.

Replace (integer progression) preprocessor constants with enumeration
type.
Signed-off-by: Tobin C. Harding <me@tobin.cc>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>