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/pxm2_defconfig b/configs/pxm2_defconfig
index 7a53016..95ab0a3 100644
--- a/configs/pxm2_defconfig
+++ b/configs/pxm2_defconfig
@@ -2,6 +2,7 @@
 CONFIG_TARGET_PXM2=y
 CONFIG_SPL=y
 CONFIG_FIT=y
+CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="U-Boot# "
 CONFIG_AUTOBOOT_KEYED=y
 CONFIG_AUTOBOOT_PROMPT="Autobooting in %d seconds, press \"<Esc><Esc>\" to stop\n"