dt-bindings: arm: update vexpress-config.yaml references

Changeset 7e8339b5162f ("dt-bindings: arm: convert vexpress-config to DT schema")
renamed: Documentation/devicetree/bindings/arm/vexpress-sysreg.txt
to: Documentation/devicetree/bindings/arm/vexpress-config.yaml.

Update the cross-references accordingly.

Fixes: 7e8339b5162f ("dt-bindings: arm: convert vexpress-config to DT schema")
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>
Acked-by: Guenter Roeck <[e-mail]>
Signed-off-by: Rob Herring <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

Documentation/devicetree/bindings/hwmon/vexpress.txt

···
 	"arm,vexpress-power"
 	"arm,vexpress-energy"
 - "arm,vexpress-sysreg,func" when controlled via vexpress-sysreg
-  (see Documentation/devicetree/bindings/arm/vexpress-sysreg.txt
+  (see Documentation/devicetree/bindings/arm/vexpress-config.yaml
   for more details)
 
 Optional node properties:

Documentation/devicetree/bindings/regulator/vexpress.txt

···
 Requires node properties:
 - "compatible" value: "arm,vexpress-volt"
 - "arm,vexpress-sysreg,func" when controlled via vexpress-sysreg
-  (see Documentation/devicetree/bindings/arm/vexpress-sysreg.txt
+  (see Documentation/devicetree/bindings/arm/vexpress-config.yaml
   for more details)
 
 Required regulator properties: