sandbox: i2c_emul_find() No emulators for device 'rtc@43'

when running the date command on sandbox_defconfig an error occurs:

    ./u-boot -D u-boot.dtb

    => date
    i2c_emul_find() No emulators for device 'rtc@43'
    ## Get date failed

Correct the references to the emulator devices in the sandbox device trees
using test.dts as a reference.

Fixes: 031a650e ("dm: sandbox: i2c: Use new emulator parent uclass")
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Dropped unnecessary #address/size-cells property in i2c_emul:
Signed-off-by: Simon Glass <sjg@chromium.org>