staging: r8188eu: remove unused PATH_LENGTH_MAX define

PATH_LENGTH_MAX in osdep_service.h is not used and can
be removed.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20220115165536.231210-5-martin@kaiser.cx


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