Fix AMD 8132 and 8151 southbridge builds

Fix AMD 8132 and 8151 southbridge builds

Untested, changes ramstage build for boards:
  supermicro/h8qme_fam10
  amd/serengeti_cheetah
  amd/serengeti_cheetah_fam10

AMD 8132 was not built for any mainboard due to a typo.

AMD Serengeti Cheetah:
  Chip 8151 is referenced in devicetree.cb but was not built.

AMD Serengeti Cheetah Family10:
  There are indications the board has 8151, but it is not listed
  in the devicetree.cb. The 8151 chip is not added in the build.

Change-Id: I03acdfcc3f3440bd32e81a9a696159903bbbcb50
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/471
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marcj303@gmail.com>