i2c recovery can spend an eternity in OPAL

https://github.com/open-power/skiboot/commit/cf6ec98fe79c59fd5de5c5a77917913af8d2cede#diff-2b91884ca2338aa38cdbcd221e9b1aec

Hacky workaround for some "interesting" i2c issues will some day bite us. We should do it better.