kconfig: move initramfs options to General Setup

Move initramfs options from Device Drivers | Block Drivers to General Setup
This is a more natural place for this option.

Furthermore separate out intramfs options to usr/Kconfig

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

init/Kconfig

@@ -238,6 +238,8 @@ config CPUSETS
 
 	  Say N if unsure.
 
+source "usr/Kconfig"
+
 menuconfig EMBEDDED
 	bool "Configure standard kernel features (for small systems)"
 	help