image_types_wic.bbclass: add "grub-efi" back to WKS_FILE_DEPENDS_BOOTLOADERS on x86-64

image_types_wic.bbclass: add "grub-efi" back to WKS_FILE_DEPENDS_BOOTLOADERS on x86-64

This was removed by me without good reasons in commit
2f0ef8cd0e61c34e67ad9c7508094da3c23f5fce
"wic bootimg-efi.py: change UKI support from wic plugin to uki.bbclass"
and results in grub-efi binaries missing from
genereted ESP partition on qemux86-64.

Fixes oeqa selftest
overlayfs.OverlayFSEtcRunTimeTests.test_image_feature_is_missing
after wic detects missing EFI loader files on ESP partition.

Test case was passing due qemu syslinux boot using kernel directly
from /boot and not using UEFI firmware to boot.

Fixes: 2f0ef8cd0e61 ("wic bootimg-efi.py: change UKI support from wic plugin to uki.bbclass")
WKS_FILE_DEPENDS_BOOTLOADERS needs to list all EFI loaders because
it's used in DEPENDS and thus can't use conditional python macros
to select which loader is actually needed in sysroot when
wic builds the images and ESP partition.

Signed-off-by: Mikko Rapeli <mikko.rapeli@linaro.org>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>