linux: make it possible to install the kernel in /boot

[Peter: always copy to output/images as requested by Luca]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

linux/Config.in

@@ -153,6 +153,14 @@ config BR2_LINUX_KERNEL_IMAGE_TARGET_NAME
 	  Specify the kernel make target to build the kernel that you
 	  need.
 
+config BR2_LINUX_KERNEL_INSTALL_TARGET
+	bool "Install kernel image to /boot in target"
+	depends on !BR2_TARGET_ROOTFS_INITRAMFS
+	help
+	  Select this option to have the kernel image installed to
+	  /boot in the target root filesystem, as is typically done on
+	  x86/x86_64 systems.
+
 endif # BR2_LINUX_KERNEL
 
 endmenu

linux/linux.mk

@@ -157,6 +157,9 @@ $(LINUX26_DIR)/.stamp_compiled: $(LINUX26_DIR)/.stamp_configured $(LINUX26_DIR)/
 # Installation
 $(LINUX26_DIR)/.stamp_installed: $(LINUX26_DIR)/.stamp_compiled
 	@$(call MESSAGE,"Installing kernel")
+ifeq ($(BR2_LINUX_KERNEL_INSTALL_TARGET),y)
+	install -m 0644 -D $(LINUX26_IMAGE_PATH) $(TARGET_DIR)/boot/$(LINUX26_IMAGE_NAME)
+endif
 	cp $(LINUX26_IMAGE_PATH) $(BINARIES_DIR)
 	# Install modules and remove symbolic links pointing to build
 	# directories, not relevant on the target