This patch enables bsdinstall to create EFI partition during installation and uploading it's contents,
making the ARM64 FreeBSD installation bootable.

Obtained from:         Semihalf
Sponsored by:          Cavium
Approved by:           re
Reviewed by:           allanjude, emaste, nwhitehorn, wma
Differential Revision: https://reviews.freebsd.org/D6853