wifi: wireless: declare different S1G chandefs incompatible

It doesn't look like we can get into this code, but make it
more robust and declare two S1G chandefs to be incompatible
unless they're identical.

Link: https://msgid.link/20240129194108.b28fb0644a8c.I9297ada5cf1baf00dbbdf8fcffd1806883489fc9@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>