arm64: Align the kbuild output for VDSOL and VDSOA

Signed-off-by: Ian Campbell <ijc@hellion.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Michal Marek <mmarek@suse.cz>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kbuild@vger.kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>