staging: r8188eu: merge on_action_public_vendor into its caller

Apart from declaring variables, on_action_public_vendor is only an if
statement. Merge this function into its only caller. This makes the code a
tiny bit smaller.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Link: https://lore.kernel.org/r/20221230175326.90617-2-martin@kaiser.cx


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