ARM: dts: imx28-cfa10049: fix dtc warning

This fixes the following dtc warning by removing the unnecessary unit:

Warning (unit_address_vs_reg): Node /onewire@0 has a unit name,
but no reg property

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>