dt-bindings: usb/ti,am62-usb.yaml: Add PHY2 register space

Add PHY2 register space to DT binding documentation.

We use minItems: 1 as DT update will come later and we don't
want warnings for existing DTs.

So far this register space was not required but due to the
newly identified Errata i2409 [1] we need to poke this
register space.

[1] https://www.ti.com/lit/er/sprz487d/sprz487d.pdf

Signed-off-by: Roger Quadros <[e-mail]>
Acked-by: Rob Herring <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/devicetree/bindings/usb/ti,am62-usb.yaml

···
     const: ti,am62-usb
 
   reg:
-    maxItems: 1
+    minItems: 1
+    items:
+      - description: USB CFG register space
+      - description: USB PHY2 register space
 
   ranges: true
 
···
 
       usbss1: usb@f910000 {
         compatible = "ti,am62-usb";
-        reg = <0x00 0x0f910000 0x00 0x800>;
+        reg = <0x00 0x0f910000 0x00 0x800>,
+              <0x00 0x0f918000 0x00 0x400>;
         clocks = <&k3_clks 162 3>;
         clock-names = "ref";
         ti,syscon-phy-pll-refclk = <&wkup_conf 0x4018>;