Kconfig: move EXPERT option under "General setup" menu

Make it a sub-menu of "General setup" like Linux Kernel.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Tom Rini <trini@ti.com>
diff --git a/Kconfig b/Kconfig
index 153ee2b..60cf1dd 100644
--- a/Kconfig
+++ b/Kconfig
@@ -56,8 +56,6 @@
 
 	  This option is enabled by default for U-Boot.
 
-endmenu		# General setup
-
 menuconfig EXPERT
         bool "Configure standard U-Boot features (expert users)"
         help
@@ -66,6 +64,8 @@
           environments which can tolerate a "non-standard" U-Boot.
           Only use this if you really know what you are doing.
 
+endmenu		# General setup
+
 menu "Boot images"
 
 config SPL_BUILD