staging: r8188eu: remove unnecessary variable in ioctl_linux

Returning value 0 directly instead of storing it in variable ret.
This commit can prevent cocci warning as follows:

  Unneeded variable: "ret". Return "0" on line 3030

Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Signed-off-by: Kang Minchul <tegongkang@gmail.com>
Link: https://lore.kernel.org/r/20221025170621.271903-2-tegongkang@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>