core: move reproducible option to advanced sub-menu

The reproducible build is only in its infancy; it is far from being
complete.

As such, move it to the "advanced" build sub-menu, where it belong for
now...

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

Config.in

@@ -726,8 +726,6 @@ config BR2_COMPILER_PARANOID_UNSAFE_PATH
 	  toolchain (through the toolchain wrapper and binutils patches)
 	  and external toolchain backends (through the toolchain wrapper).
 
-endmenu
-
 config BR2_REPRODUCIBLE
 	bool "Make the build reproducible (experimental)"
 	help
@@ -741,6 +739,8 @@ config BR2_REPRODUCIBLE
 
 endmenu
 
+endmenu
+
 source "toolchain/Config.in"
 
 source "system/Config.in"