dt-bindings: pci: pcie-brcmstb: add optional brcm,tperst-clk-ms property

Some platforms may require an extended time with refclk active before
PERST# is released. Add a property to let the RC driver know how long to
wait.

Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>

Author: P33M

Documentation/devicetree/bindings/pci/brcm,stb-pcie.yaml

@@ -104,6 +104,12 @@ properties:
     minItems: 1
     maxItems: 3
 
+  brcm,tperst-clk-ms:
+    description: u32 giving the number of milliseconds to extend
+      the time between internal release of fundamental reset and
+      the deassertion of the external PERST# pin. This has the
+      effect of increasing the Tperst_clk phase of link init.
+
   brcm,vdm-qos-map:
     description: Array of u8 elements which assigns each per-TC FIFO
       a base AXI priority with automatic elevation depending on