staging: rtl8188eu: core: switch with redundant cases

A few redundant switch cases as well as a redundant if/else
within one of the cases was consolidated to a single call.
The cases are intentionally retained for documentation purposes.

case WIFI_REASSOCREQ,WIFI_PROBEREQ,WIFI_BEACON,WIFI_ACTION all
have the same effect - notably the also for WIFI_PROBEREQ where
the if/else is executing the same function.

These redundant cases could all be dropped and consolidated into
the default but probably it is better for documentation/readability
to leave them in the switch/case explicitly.

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>