samples: sensor/mcux_acmp: Support ACMP case on mimxrt700_evk

1. Supported ACMP case on mimxrt700_evk
2. Fixed the issue of using the same address for
different trigger sources. This bug would cause the
examples to run in a way that did not match the theory.
3. Removed some redundant descriptions in the README.rst.

Signed-off-by: Zhaoxiang Jin <Zhaoxiang.Jin_1@nxp.com>