Revert "bcm_sta: update to 6.20.155.1"

This reverts commit 299d664a9be686526ce767724b58441976782b5d.
Revert "Merge branch 'osx-livestick'"

This reverts commit f947a9282c20eb5ae1d2e9aba4b6593c75139008, reversing
changes made to 299d664a9be686526ce767724b58441976782b5d.