ARM: dts: keystone-evm: add 1g ethernet phys nodes

Keystone EVMK2HX has two 1G Marvell 88E1111 Ethernet PHYs
installed, so add corresponding child nodes for 1G MDIO bus
and enable it.

For more information see schematics:
 http://wfcache.advantech.com/www/support/TI-EVM/download/Schematics/PDF/K2H_K2EVM-HK_SCH_A102_Rev1_0.pdf



Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>