configs: Re-sync HUSH options

Move all cases of CONFIG_SYS_HUSH_PARSER out of the config.h files.  Remove
all cases of CONFIG_SYS_PROMPT_HUSH_PS2 as everyone uses the default.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/yellowstone_defconfig b/configs/yellowstone_defconfig
index 773e93b..4f76e37 100644
--- a/configs/yellowstone_defconfig
+++ b/configs/yellowstone_defconfig
@@ -3,5 +3,6 @@
 CONFIG_TARGET_YOSEMITE=y
 CONFIG_OF_BOARD_SETUP=y
 CONFIG_SYS_EXTRA_OPTIONS="YELLOWSTONE"
+CONFIG_HUSH_PARSER=y
 CONFIG_SYS_NS16550=y
 CONFIG_OF_LIBFDT=y