net: phy: mtk-2p5ge: Add LED support for MT7988

net: phy: mtk-2p5ge: Add LED support for MT7988

Add LED support for MT7988's built-in 2.5Gphy. LED hardware has almost
the same design with MT7981's/MT7988's built-in GbE. So hook the same
helper function here.

Before mtk_phy_leds_state_init(), set correct default values of LED0
and LED1.

Signed-off-by: Sky Huang <skylake.huang@mediatek.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20250827044755.3256991-1-SkyLake.Huang@mediatek.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>