arm64: properly install vmlinuz.efi

arm64: properly install vmlinuz.efi

If you select CONFIG_EFI_ZBOOT, we will generate vmlinuz.efi, and then
when we go to install the kernel we'll install the vmlinux instead
because install.sh only recognizes Image.gz as wanting the compressed
install image.  With CONFIG_EFI_ZBOOT we don't get the proper kernel
installed, which means it doesn't boot, which makes for a very confused
and subsequently angry kernel developer.

Fix this by properly installing our compressed kernel if we've enabled
CONFIG_EFI_ZBOOT.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Cc: <stable@vger.kernel.org> # 6.1.x
Fixes: c37b830fef13 ("arm64: efi: enable generic EFI compressed boot")
Reviewed-by: Simon Glass <sjg@chromium.org>
Link: https://lore.kernel.org/r/6edb1402769c2c14c4fbef8f7eaedb3167558789.1702570674.git.josef@toxicpanda.com
Signed-off-by: Will Deacon <will@kernel.org>