brcmfmac: make chandef_to_chanspec() function static

The function chandef_to_chanspec() was added by

    brcmfmac: determine chanspec from struct cfg80211_chan_def info

    The struct cfg80211_chan_def contains additional info to derive the
    bandwidth and side-band information of the chanspec. This patch adds
    chandef_to_chanspec() function used in IBSS join and starting AP
    operation.

However, it introduced a sparse warning because the function
is only called from within the source file wl_cfg80211.c.
Reported-by: NFengguang Wu <fengguang.wu@intel.com>
Reviewed-by: NDaniel (Deognyoun) Kim <dekim@broadcom.com>
Reviewed-by: NHante Meuleman <meuleman@broadcom.com>
Signed-off-by: NArend van Spriel <arend@broadcom.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/brcm80211/brcmfmac/wl_cfg80211.c

@@ -341,8 +341,8 @@ static u8 brcmf_mw_to_qdbm(u16 mw)
 	return qdbm;
 }
 
-u16 chandef_to_chanspec(struct brcmu_d11inf *d11inf,
-			struct cfg80211_chan_def *ch)
+static u16 chandef_to_chanspec(struct brcmu_d11inf *d11inf,
+			       struct cfg80211_chan_def *ch)
 {
 	struct brcmu_chan ch_inf;
 	s32 primary_offset;