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/mx51evk_defconfig b/configs/mx51evk_defconfig
index 0bb0c61..4dd2f78 100644
--- a/configs/mx51evk_defconfig
+++ b/configs/mx51evk_defconfig
@@ -1,6 +1,7 @@
 CONFIG_ARM=y
 CONFIG_TARGET_MX51EVK=y
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=board/freescale/mx51evk/imximage.cfg"
+CONFIG_HUSH_PARSER=y
 # CONFIG_CMD_IMLS is not set
 # CONFIG_CMD_SETEXPR is not set
 CONFIG_OF_LIBFDT=y