dt-bindings: iio/accel: Fix adi,adxl345/6 example I2C address

dt-bindings: iio/accel: Fix adi,adxl345/6 example I2C address

Align the example node address and reg content to be 0x2a for both.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandru Ardelean <alexandru.ardelean@analog.com>
Cc: Hartmut Knaack <knaack.h@gmx.de>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Michael Hennerich <michael.hennerich@analog.com>
Cc: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-iio@vger.kernel.org
Cc: devicetree@vger.kernel.org
Link: https://lore.kernel.org/r/20220615233411.90621-1-marex@denx.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>