staging: rtl8188eu: simplify rtl88eu_mon_init

The code looks a bit nicer without goto.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20210620175301.14988-9-martin@kaiser.cx


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