w1: ds2438: fixed if brackets coding style issue

Since there is only one statement inside the if clause, no brackets are
required.

Signed-off-by: Luiz Sampaio <sampaio.ime@gmail.com>
Link: https://lore.kernel.org/r/20210519223046.13798-3-sampaio.ime@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>