net: stmmac: fix incorrect flag check in timestamp interrupt

The driver should continue get the timestamp if STMMAC_FLAG_EXT_SNAPSHOT_EN
flag is set.

Fixes: aa5513f ("net: stmmac: replace the ext_snapshot_en field with a flag")
Cc: <stable@vger.kernel.org> # 6.6
Signed-off-by: Song Yoong Siang <yoong.siang.song@intel.com>
Signed-off-by: Lai Peter Jun Ann <jun.ann.lai@intel.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c

@@ -237,7 +237,7 @@ static void timestamp_interrupt(struct stmmac_priv *priv)
 	 */
 	ts_status = readl(priv->ioaddr + GMAC_TIMESTAMP_STATUS);
 
-	if (priv->plat->flags & STMMAC_FLAG_EXT_SNAPSHOT_EN)
+	if (!(priv->plat->flags & STMMAC_FLAG_EXT_SNAPSHOT_EN))
 		return;
 
 	num_snapshot = (ts_status & GMAC_TIMESTAMP_ATSNS_MASK) >>