arch: mips: brcm: Add 7425 flash-edu support

Nand controller v5.0 and v6.0 have nand edu blocks that enable
dma nand flash transfers. This allows for faster read and write
access.

Signed-off-by: Kamal Dasu <[e-mail]>
Acked-by: Paul Burton <[e-mail]>
Reviewed-by: Florian Fainelli <[e-mail]>
Signed-off-by: Miquel Raynal <[e-mail]>
Link: https://lore.kernel.org/linux-mtd/[e-mail]

arch/mips/boot/dts/brcm/bcm7425.dtsi

···
 			compatible = "brcm,brcmnand-v5.0", "brcm,brcmnand";
 			#address-cells = <1>;
 			#size-cells = <0>;
-			reg-names = "nand";
-			reg = <0x41b800 0x400>;
+			reg-names = "nand", "flash-edu";
+			reg = <0x41b800 0x400>, <0x41bc00 0x24>;
 			interrupt-parent = <&hif_l2_intc>;
 			interrupts = <24>;
 			status = "disabled";