staging: r8188eu: remove unused macro ROUND

The macro ROUND is not used in the driver, remove it.
Found with GCC -Wunused-macros.

Acked-by: Martin Kaiser <martin@kaiser.cx>
Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20210909202130.28508-1-straube.linux@gmail.com


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