Define common functions for populating EFI directories in live image by
reusing common code from grub-efi and systemd-boot bbclasses.
(From OE-Core rev: 3728899a0cd543793db258da0976362b4bde7133)
Signed-off-by: Dmitry Eremin-Solenikov <dmitry_eremin-solenikov@mentor.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>