staging: dgnc: remove explicit cast

Function return type is 'int'. Returned variable is of type
'uint'. uint can be implicitly converted to int. Most significant bit
is not set so there is no risk in implicit conversion.

Remove unnecessary type cast.

Signed-off-by: Tobin C. Harding <me@tobin.cc>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>