mb/google/poppy: Add lens_focus property for OV13858 camera module

Add lens_focus property with reference to VCM device for OV13858
camera module to register the corresponding v4l2 sub-device
asynchronously.

BUG=b:64133998
BRANCH=none
TEST=Build and boot soraka. Dump DSDT and verified that it has the
required entries and verified the camera functionality.

Change-Id: Ib22403f668dd07d6b9226fe2c22b533223b69473
Signed-off-by: V Sowmya <v.sowmya@intel.com>
Reviewed-on: https://review.coreboot.org/21512
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/poppy/acpi/mipi_camera.asl

@@ -649,8 +649,10 @@ Scope (\_SB.PCI0.I2C2)
 			ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
 			Package () {
 				Package () { "clock-frequency", 19200000 },
+				Package () { "lens-focus",
+					Package () { \_SB.PCI0.I2C2.VCM0 }
+				}
 			}
-
 		})
 
 		Name (PRT0, Package() {