This removes CONFIG_BOOTSTAGE_USER_COUNT, CONFIG_BOOTSTAGE_STASH_ADDR
and CONFIG_BOOTSTAGE_STASH_SIZE from defconfig following boards:

  - Alt
  - Gose
  - Koelsh
  - Lager
  - Porter
  - Silk
  - Stout
  - Blanche
  - Salvator-x
Signed-off-by: NNobuhiro Iwamatsu <iwamatsu@nigauri.org>