bnxt_en: Do not enable legacy TX push on older firmware.

Older firmware may not support legacy TX push properly and may not
be disabling it.  So we check certain firmware versions that may
have this problem and disable legacy TX push unconditionally.

Fixes: c0c050c5 ("bnxt_en: New Broadcom ethernet driver.")
Reviewed-by: NEdwin Peer <edwin.peer@broadcom.com>
Signed-off-by: NMichael Chan <michael.chan@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -6976,7 +6976,8 @@ static int __bnxt_hwrm_func_qcaps(struct bnxt *bp)
 		bp->fw_cap |= BNXT_FW_CAP_ERR_RECOVER_RELOAD;
 
 	bp->tx_push_thresh = 0;
-	if (flags & FUNC_QCAPS_RESP_FLAGS_PUSH_MODE_SUPPORTED)
+	if ((flags & FUNC_QCAPS_RESP_FLAGS_PUSH_MODE_SUPPORTED) &&
+	    BNXT_FW_MAJ(bp) > 217)
 		bp->tx_push_thresh = BNXT_TX_PUSH_THRESH;
 
 	hw_resc->max_rsscos_ctxs = le16_to_cpu(resp->max_rsscos_ctx);

drivers/net/ethernet/broadcom/bnxt/bnxt.h

@@ -1749,6 +1749,7 @@ struct bnxt {
 	u64			fw_ver_code;
 #define BNXT_FW_VER_CODE(maj, min, bld, rsv)			\
 	((u64)(maj) << 48 | (u64)(min) << 32 | (u64)(bld) << 16 | (rsv))
+#define BNXT_FW_MAJ(bp)		((bp)->fw_ver_code >> 48)
 
 	__be16			vxlan_port;
 	u8			vxlan_port_cnt;