rtlwifi: constify rate_control_ops structure

rate_control_ops structure is only passed as an argument to the
function ieee80211_rate_control_{register/unregister}. This argument
is of type const, so declare the structure as const.
Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/realtek/rtlwifi/rc.c

@@ -283,7 +283,7 @@ static void rtl_rate_free_sta(void *rtlpriv,
 	kfree(rate_priv);
 }
 
-static struct rate_control_ops rtl_rate_ops = {
+static const struct rate_control_ops rtl_rate_ops = {
 	.name = "rtl_rc",
 	.alloc = rtl_rate_alloc,
 	.free = rtl_rate_free,