staging: brcm80211: move PCI related header files to appropriate driver folder

The include file pcicfg.h is now only required by brcmfmac driver. Similarly,
nicpci.h is only required by brcmsmac driver. These header files have been
moved to the appropriate driver specific folder.
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Reviewed-by: Roland Vossen <rvossen@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>