kernel.mk: fix kernel targets for arm and arm64

Use the Image.gz kernel target for arm64 to be able append DTB to kernel
bin at the end.

Also remove zImage-dtb for arm: v4.1 and v4.4 kernels do not have this target.
zImage-dtb is defined only in the android-3.18 kernel:
    $(obj)/zImage-dtb:  $(obj)/zImage $(DTB_OBJS) FORCE
        $(call if_changed,cat)

The same thing implemented inside kernel.mk if TARGET_KERNEL_DTB_APPEND is
defined.
So, the zImage-dtb use is not necessary and will produce an
error if arm platform will not define TARGET_KERNEL_DTB.
Steps to verify it: just remove TARGET_KERNEL_DTB defenition from
brilloemulator_arm/bsp/qemu_arm.mk and try to build a kernel.

BUG: 27674989

Change-Id: I09e06b7f474df77f61b2f99d18628d4fc1bd5d89
Signed-off-by: Dzmitry Yatsushkevich <dmitryya@nestlabs.com>
1 file changed