hwmon: (lm90) Drop critical attribute support for MAX6654

Tests with a real chip and a closer look into the datasheet show that
MAX6654 does not support CRIT/THERM/OVERTEMP limits, so drop support
of the respective attributes for this chip.

Introduce LM90_HAVE_CRIT flag and use it to instantiate critical limit
attributes to solve the problem.

Cc: Josh Lehan <krellan@google.com>
Fixes: 229d495d ("hwmon: (lm90) Add max6654 support to lm90 driver")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>