Add fake reg property to irq-syscfg node.
This allows to fix the following warning when compiling
dtb with W=1 option:
arch/arm/boot/dts/stih407-b2120.dtb: Warning (simple_bus_reg):
Node /soc/irq-syscfg missing or empty reg/ranges property
arch/arm/boot/dts/stih410-b2120.dtb: Warning (simple_bus_reg):
Node /soc/irq-syscfg missing or empty reg/ranges property
arch/arm/boot/dts/stih410-b2260.dtb: Warning (simple_bus_reg):
Node /soc/irq-syscfg missing or empty reg/ranges property
arch/arm/boot/dts/stih418-b2199.dtb: Warning (simple_bus_reg):
Node /soc/irq-syscfg missing or empty reg/ranges property
Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
                        reg = <0x94b5100 0x1000>;
                };
 
-               irq-syscfg {
+               irq-syscfg@0 {
                        compatible    = "st,stih407-irq-syscfg";
+                       reg = <0 0>;
                        st,syscfg     = <&syscfg_core>;
                        st,irq-device = <ST_IRQ_SYSCFG_PMU_0>,
                                        <ST_IRQ_SYSCFG_PMU_1>;