Fix usage of "temp" instead of "temper" in spice models.

Fixes https://github.com/google/skywater-pdk/issues/171.

In ngspice (and also spectre), temperature that appears in a parameter
equation should use the name "temper", not "temp".

Signed-off-by: diadatp <admin@diadatp.com>
Signed-off-by: Stefan Schippers <schippes@mazinga.lan>
Signed-off-by: Tim Edwards <tim@opencircuitdesign.com>
Signed-off-by: Tim 'mithro' Ansell <me@mith.ro>