dt-bindings: net: stmmac: remove syscfg clock property

- clock-names: Should be "stmmaceth" for the host clock.

	       Should be "mac-clk-tx" for the MAC TX clock.

	       Should be "mac-clk-rx" for the MAC RX clock.

	       For MPU family need to add also "ethstp" for power mode clock and,

	                                       "syscfg-clk" for SYSCFG clock.

	       For MPU family need to add also "ethstp" for power mode clock

- interrupt-names: Should contain a list of interrupt names corresponding to

           the interrupts in the interrupts property, if available.

		   Should be "macirq" for the main MAC IRQ