staging: r8188eu: remove unused define

_HCI_OPS_OS_C_ is not used in the r8188eu driver. Remove it.

Acked-by: Michael Straube <straube.linux@gmail.com>
Acked-by: Phillip Potter <phil@philpotter.co.uk>
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20210821164859.4351-2-martin@kaiser.cx


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