dt-bindings: usb: dwc3: Deprecate snps,ref-clock-period-ns

This property is redundant because we can determine the correct value for
REFCLKPER based on the "ref" clock. Deprecate it, and encourage users to
provide a clock instead. This also restricts the minimum and maximum to the
values documented in the register reference [1].

[1] https://www.xilinx.com/html_docs/registers/ug1087/usb3_xhci___guctl.html

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
Link: https://lore.kernel.org/r/20220127200636.1456175-2-sean.anderson@seco.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/usb/snps,dwc3.yaml

@@ -263,8 +263,11 @@ properties:
       Value for REFCLKPER field of GUCTL register for reference clock period in
       nanoseconds, when the hardware set default does not match the actual
       clock.
-    minimum: 1
-    maximum: 0x3ff
+
+      This binding is deprecated. Instead, provide an appropriate reference clock.
+    minimum: 8
+    maximum: 62
+    deprecated: true
 
   snps,rx-thr-num-pkt-prd:
     description: