hwmon: (nct6775) Fix loop limit

hwmon: (nct6775) Fix loop limit

Commit cc66b3038254 ("hwmon: (nct6775) Rework temperature source and label
handling") changed a loop limit from "data->temp_label_num - 1" to "32",
as part of moving from a string array to a bit mask. This results in the
following error, reported by UBSAN.

UBSAN: Undefined behaviour in drivers/hwmon/nct6775.c:4179:27
shift exponent 32 is too large for 32-bit type 'long unsigned int'

Similar to the original loop, the limit has to be one less than the
number of bits.

Fixes: cc66b3038254 ("hwmon: (nct6775) Rework temperature source and label handling")
Reported-by: Paul Menzel <[email protected]>
Cc: Paul Menzel <[email protected]>
Tested-by: Paul Menzel <[email protected]>
Signed-off-by: Guenter Roeck <[email protected]>