staging: r8188eu: handle rtw_write8 errors in SwLedOn

Check the status returned by rtw_write8. Update bLedOn only if we could
update the REG_LEDCFG2 register.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Link: https://lore.kernel.org/r/20221015151115.232095-3-martin@kaiser.cx


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