Kconfig: Create a new 'init options' menu

There are quite a few options at the top level relating to U-Boot init.
Move them into their own menu.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/common/Kconfig b/common/Kconfig
index 6423ab3..3aa8cf3 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -433,6 +433,8 @@
 
 endmenu
 
+menu "Init options"
+
 config MISC_INIT_R
 	bool "Execute Misc Init"
 	default y if ARCH_KEYSTONE || ARCH_SUNXI || MPC85xx
@@ -483,6 +485,8 @@
 	  the relocation phase. The board function checkboard() is called to do
 	  this.
 
+endmenu		# Init options
+
 config BOUNCE_BUFFER
 	bool "Include bounce buffer API"
 	help