mwifiex: fix wrong 11ac bits setting in fw_cap_info

bit 14 is actually reserved and bit 12 & 13 should be used for
11ac capability in fw_cap_info.

Cc: <stable@vger.kernel.org> # 3.9+
Signed-off-by: NBing Zhao <bzhao@marvell.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mwifiex/fw.h

@@ -226,7 +226,7 @@ enum MWIFIEX_802_11_PRIVACY_FILTER {
 
 /* HW_SPEC fw_cap_info */
 
-#define ISSUPP_11ACENABLED(fw_cap_info) (fw_cap_info & (BIT(13)|BIT(14)))
+#define ISSUPP_11ACENABLED(fw_cap_info) (fw_cap_info & (BIT(12)|BIT(13)))
 
 #define GET_VHTCAP_CHWDSET(vht_cap_info)    ((vht_cap_info >> 2) & 0x3)
 #define GET_VHTNSSMCS(mcs_mapset, nss) ((mcs_mapset >> (2 * (nss - 1))) & 0x3)