staging: brcm80211: removed unused bus code from softmac

Code cleanup. For the softmac, the 'bustype' in use is always PCI_BUS. Hence
code related to dealing with different bus types (eg: PCI_BUS, JTAG_BUS,
SI_BUS) could be removed.

Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>