staging: brcm80211: remove duplicated code from brcmf_init_iscan

Part of the code in brcmf_init_scan was identical to the code in
brcmf_invoke_iscan and has been replaced by a call to it.

Signed-off-by: Arend van Spriel <arend@broadcom.com>
Reviewed-by: Roland Vossen <rvossen@broadcom.com>
Reviewed-by: Franky Lin <frankyl@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>