dt-bindings: clk: microchip: mpfs: add reset controller support

The "peripheral" devices on PolarFire SoC can be put into reset, so
update the device tree binding to reflect the presence of a reset
controller.

Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Daire McNamara <daire.mcnamara@microchip.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20220909123123.2699583-4-conor.dooley@microchip.com

Documentation/devicetree/bindings/clock/microchip,mpfs.yaml

@@ -40,8 +40,21 @@ properties:
     const: 1
     description: |
       The clock consumer should specify the desired clock by having the clock
-      ID in its "clocks" phandle cell. See include/dt-bindings/clock/microchip,mpfs-clock.h
+      ID in its "clocks" phandle cell.
-      for the full list of PolarFire clock IDs.
+      See include/dt-bindings/clock/microchip,mpfs-clock.h for the full list of
+      PolarFire clock IDs.
+
+  resets:
+    maxItems: 1
+
+  '#reset-cells':
+    description:
+      The AHB/AXI peripherals on the PolarFire SoC have reset support, so from
+      CLK_ENVM to CLK_CFM. The reset consumer should specify the desired
+      peripheral via the clock ID in its "resets" phandle cell.
+      See include/dt-bindings/clock/microchip,mpfs-clock.h for the full list of
+      PolarFire clock IDs.
+    const: 1
 
 required:
   - compatible