staging: r8188eu: handle the non-ap case first

The OnDisassoc function hasn't got much to do if we're not working as an
access point. Move this case out of the large if statement to simplify the
code.

Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20221129205152.128172-5-martin@kaiser.cx


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