Current SBE breaks backwards compatibility with older hostboot

SBE as of op-build 2251a24d7c555878e0fc9fe04bed856375c98e89 will not load the hostboot as of op-build a733e80a16179935b4d69fc85b1b04b42e53a34a

This corresponds to SBE cf61dc3 not booting hostboot 876b79aacd9b14f4c3561e954daa0285747c9662

[sgupta2m]

based on discussion on hostboot channel, it seems we have compatibility issue between hbbl in b0821a_1832.910 and 876b79aacd9b14f4c3561e954daa0285747c9662.

This issue needs to go to HB project. @dcrowell77 want to take a stab on it ?