brcm80211: fmac: changed two scan related structures

struct brcmf_scan_results contained a 1 element array, but in reality
the number of scan results can be 0 or more, as indicated by the
count field in the same struct. Array has be redefined to be 0 elements
length to indicate the array is purely for reference.

Reported-by: Johannes Berg <johannes@sipsolutions.net>
Reviewed-by: Arend van Spriel <arend@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Signed-off-by: Roland Vossen <rvossen@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>