net: dsa: mt7530: Refine message in Kconfig

Refine message in Kconfig with fixing typo and an explicit MT7621 support.
Signed-off-by: Landen Chao <landen.chao@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/Kconfig

@@ -33,12 +33,12 @@ config NET_DSA_LANTIQ_GSWIP
 	  the xrx200 / VR9 SoC.
 
 config NET_DSA_MT7530
-	tristate "Mediatek MT7530 Ethernet switch support"
+	tristate "MediaTek MT7530 and MT7621 Ethernet switch support"
 	depends on NET_DSA
 	select NET_DSA_TAG_MTK
 	help
-	  This enables support for the Mediatek MT7530 Ethernet switch
-	  chip.
+	  This enables support for the MediaTek MT7530 and MT7621 Ethernet
+	  switch chip.
 
 config NET_DSA_MV88E6060
 	tristate "Marvell 88E6060 ethernet switch chip support"