net: ethernet: mediatek: rename Kconfig prompt

We'll soon by adding a second MediaTek Ethernet driver so modify the
Kconfig prompt.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mediatek/Kconfig

 # SPDX-License-Identifier: GPL-2.0-only
 config NET_VENDOR_MEDIATEK
-	bool "MediaTek ethernet driver"
+	bool "MediaTek devices"
 	depends on ARCH_MEDIATEK || SOC_MT7621 || SOC_MT7620
 	---help---
 	  If you have a Mediatek SoC with ethernet, say Y.