linux: do not install images in subdirectories

linux: do not install images in subdirectories

The Linux kernel image is typically found in arch/ARCH/boot/, which is
why LINUX_IMAGE_PATH is defined as:

LINUX_IMAGE_PATH = $(LINUX_ARCH_PATH)/boot/$(LINUX_IMAGE_NAME)

However, on MIPS, some kernel image types are available from
arch/mips/boot/compressed, or even at the top-level directory. For
such cases, LINUX_IMAGE_NAME might be set (using
BR2_LINUX_KERNEL_IMAGE_NAME) to values such as:

  compressed/vmlinux.bin.z

or

  ../../../uzImage.bin

Except that the line:

  $(INSTALL) -m 0644 -D $(LINUX_IMAGE_PATH) $(1)/$(LINUX_IMAGE_NAME)

will lead to such images be installed in:

  $(TARGET_DIR)/boot/compressed/vmlinux.bin.z
  $(BINARIES_DIR)/compressed/vmlinux.bin.z

and:

  $(TARGET_DIR)/boot/../../../uzImage.bin
  $(BINARIES_DIR)/../../../uzImage.bin

which of course is completely bogus.

So let's install them under their name, not their full relative path
to arch/ARCH/boot/.

Reported-by: Paul Cercueil <paul@crapouillou.net>
Cc: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>