dt-bindings: usb: npcm7xx: Add npcm845 compatible

Add a compatible string for Nuvoton BMC NPCM845 USB EHCI host controller.
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
Link: https://lore.kernel.org/r/20220718181842.61040-3-tmaimon77@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/usb/npcm7xx-usb.txt

@@ -5,7 +5,9 @@ EHCI:
 -----
 
 Required properties:
-- compatible: "nuvoton,npcm750-ehci"
+- compatible: should be one of
+    "nuvoton,npcm750-ehci"
+    "nuvoton,npcm845-ehci"
 - interrupts: Should contain the EHCI interrupt
 - reg:        Physical address and length of the register set for the device