staging: r8188eu: remove unneeded variable in rtw_p2p_get_invitation_procedure

Remove unneeded return variable that is initialized to 0 and not
assigned after.

Found using Coccinelle

Signed-off-by: Abdun Nihaal <abdun.nihaal@gmail.com>
Link: https://lore.kernel.org/r/ccec1f682fbc623381519610284530f940122d0e.1643466748.git.abdun.nihaal@gmail.com


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