bta: Remove double asterisks in comments

Double asterisks at the beginning of the line
  sed -i s,"^[*][*]"," *", bta/*/*

Double asterisks after a space
  sed -i s,"^ [*][*]\([^*]\)"," *\1", bta/*/*
  sed -i s,"^ [*][*]$"," *", bta/*/*

Test: mma -j32
Change-Id: Ib83b802c7000176683b4e7f24d1255b3c2c6c01c