arm64: fix boot image dependencies to not generate invalid images
I fixed boot image dependencies for arch/arm in commit
3939f3345050
("ARM: 8418/1: add boot image dependencies to not generate invalid
images").
I see a similar problem for arch/arm64; "make -jN Image Image.gz"
would sometimes end up generating bad images where N > 1.
Fix the dependency in arch/arm64/Makefile to avoid the race
between "make Image" and "make Image.*".
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>