Changes

sysmo_isim_sja2: use `==` operator instead if `is`

The equals operator (`==`) can be overloaded by the clases which checks
the value.
While an `is` is a direct checks directs the type and value.
The convention in python is use `==` for everything except checking for None.

Signed-off-by: Alexander Couzens <lynxis@fe80.eu>