staging: r8188eu: remove unused struct zero_bulkout_context

struct zero_bulkout_context is not used. Remove it.

Signed-off-by: Abdun Nihaal <abdun.nihaal@gmail.com>
Link: https://lore.kernel.org/r/05b72a7b045a829de6f706295d17c9f0d5fa5e2f.1644422181.git.abdun.nihaal@gmail.com


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