arm64: zynqmp: fix i2c mux bus description for m-a2197 platforms

Uncomment reg property for bus 3 in i2c mux. It is better option than
removing the whole node.

Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/f28ff644fd2c6bdf5f2e646f6bc0e1ad0c92e8be.1726219714.git.michal.simek@amd.com
3 files changed