arm64: dts: imx8mp: Fix LAN8740Ai PHY reference clock on DH electronics i.MX8M Plus...

arm64: dts: imx8mp: Fix LAN8740Ai PHY reference clock on DH electronics i.MX8M Plus DHCOM

Add missing 'clocks' property to LAN8740Ai PHY node, to allow the PHY driver
to manage LAN8740Ai CLKIN reference clock supply. This fixes sporadic link
bouncing caused by interruptions on the PHY reference clock, by letting the
PHY driver manage the reference clock and assure there are no interruptions.

This follows the matching PHY driver recommendation described in commit
bedd8d78aba3 ("net: phy: smsc: LAN8710/20: add phy refclk in support")

Fixes: 8d6712695bc8 ("arm64: dts: imx8mp: Add support for DH electronics i.MX8M Plus DHCOM and PDK2")
Signed-off-by: Marek Vasut <marek.vasut@mailbox.org>
Tested-by: Christoph Niedermaier <cniedermaier@dh-electronics.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>