Remove duplicated warning message in acpi_power_transition()

ACPI: Transitioning device [%s] to D%d\n

This warning message is printed by acpi_bus_set_power() so we don't
need to print it again.
Signed-off-by: Miguel Botón <mboton@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>