staging: r8188eu: remove usb_ops_linux.h

There's only two defines left in usb_ops_linux.h. Move those defines to
usb_ops_linux.c, where they are used.

Remove the now empty file usb_ops_linux.h.

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/20230124210108.62170-5-martin@kaiser.cx


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