rtl8192du: Remove dead code with CONFIG_DEINIT_BEFORE_INIT

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
rtl8192du: Fix problem with disabling CONFIG_CONCURRENT_MAC

In the original form, an oops resulted whenever the configuration parameter
of the title was disabled. The downside was that 4 wlanX units were created
rather than one 2.4 and one 5 GHz unit.

This commit also removes that configuration parameter.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>