sandbox: Make sandbox,emul more conventional

At present this property is a phandle but does not have a #xxx-cells
property to match it. Add one so that is works the same as gpio and clock
phandles.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/sandbox/dts/sandbox.dtsi b/arch/sandbox/dts/sandbox.dtsi
index dc933f3..7455c99 100644
--- a/arch/sandbox/dts/sandbox.dtsi
+++ b/arch/sandbox/dts/sandbox.dtsi
@@ -101,15 +101,19 @@
 		};
 
 		i2c_emul: emul {
+			u-boot,dm-pre-reloc;
 			reg = <0xff>;
 			compatible = "sandbox,i2c-emul-parent";
 			emul_eeprom: emul-eeprom {
 				compatible = "sandbox,i2c-eeprom";
 				sandbox,filename = "i2c.bin";
 				sandbox,size = <256>;
+				#emul-cells = <0>;
 			};
 			emul0: emul0 {
-				compatible = "sandbox,i2c-rtc";
+				u-boot,dm-pre-reloc;
+				compatible = "sandbox,i2c-rtc-emul";
+				#emul-cells = <0>;
 			};
 		};
 	};
diff --git a/doc/driver-model/pci-info.rst b/doc/driver-model/pci-info.rst
index 8b9faa1..251601a 100644
--- a/doc/driver-model/pci-info.rst
+++ b/doc/driver-model/pci-info.rst
@@ -125,6 +125,7 @@
 		compatible = "sandbox,pci-emul-parent";
 		emul_1f: emul@1f,0 {
 			compatible = "sandbox,swap-case";
+			#emul-cells = <0>;
 		};
 	};