Use earlgrey_es_sival opentitan branch

[nasahlpa]

A FYI for all working in ot-sca (especially @vogelpi, @vrozic, @wettermo, @m-temp) - when changing SCA code in the OpenTitan repository, please always use the earlgrey_es_sival branch as this branch reflects the HW of the bitstreams we are using here in ot-sca.