wireless: iwlwifi: iwl-scan.c: Fix build warning

Fix the following build warning:

drivers/net/wireless/iwlwifi/iwl-scan.c: In function ‘iwlagn_request_scan’:
drivers/net/wireless/iwlwifi/iwl-scan.c:572: warning: ‘cmd_len’ may be used uninitialized in this function
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-scan.c

@@ -569,7 +569,7 @@ static int iwlagn_request_scan(struct iwl_priv *priv, struct ieee80211_vif *vif)
 	struct iwl_scan_cmd *scan;
 	struct iwl_rxon_context *ctx = &priv->contexts[IWL_RXON_CTX_BSS];
 	u32 rate_flags = 0;
-	u16 cmd_len;
+	u16 cmd_len = 0;
 	u16 rx_chain = 0;
 	enum ieee80211_band band;
 	u8 n_probes = 0;