emc2103.sh: Update fan1_target and fan1_div tests

fan1_target does not accept negative numbers in the latest code.
Also, add check for fan1_div value 4.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
lineage--pem.sh: Enable all available SMBus functionality in i2c-stub

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
lm93.sh: We don't need to update functionality after all

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Add test script for ds620

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Add module test for sht21 driver

Signed-off-by: Guenter Roeck <linux@roeck-us.net>