ARM: dts: vf610-bk4: Fix qspi node description

Before this change the device tree description of qspi node for
second memory on BK4 board was wrong (applicable to old, removed
fsl-quadspi.c driver).

As a result this memory was not recognized correctly when used
with the new spi-fsl-qspi.c driver.

From the dt-bindings:

"Required SPI slave node properties:
- reg: There are two buses (A and B) with two chip selects each.
This encodes to which bus and CS the flash is connected:
<0>: Bus A, CS 0
<1>: Bus A, CS 1
<2>: Bus B, CS 0
<3>: Bus B, CS 1"

According to above with new driver the second SPI-NOR memory shall
have reg=<2> as it is connected to Bus B, CS 0.

Fixes: a67d2c52a82f ("ARM: dts: Add support for Liebherr's BK4 device (vf610 based)")
Suggested-by: Fabio Estevam <[e-mail]>
Signed-off-by: Lukasz Majewski <[e-mail]>
Reviewed-by: Fabio Estevam <[e-mail]>
Signed-off-by: Shawn Guo <[e-mail]>

arch/arm/boot/dts/vf610-bk4.dts

···
 		reg = <0>;
 	};
 
-	n25q128a13_2: flash@1 {
+	n25q128a13_2: flash@2 {
 		compatible = "n25q128a13", "jedec,spi-nor";
 		#address-cells = <1>;
 		#size-cells = <1>;
 		spi-max-frequency = <66000000>;
 		spi-rx-bus-width = <2>;
-		reg = <1>;
+		reg = <2>;
 	};
 };