staging: vchi: Get rid of C++ guards

This is an include only used by the Linux kernel, so no need to worry
about C++ compatibility.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Link: https://lore.kernel.org/r/20200527115400.31391-9-nsaenzjulienne@suse.de


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