staging: r8188eu: remove enum hardware_type

From enum hardware_type only HARDWARE_TYPE_RTL8188EU is used in the
driver. Remove the enum and define HARDWARE_TYPE_RTL8188EU.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20210903093354.12645-7-straube.linux@gmail.com


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