bsdinstall: use consistent EFI configuration across platforms
- increase arm64 EFI partition to 200M, as x86
- use EFI_BOOTPART_SIZE and EFI_BOOTPART_PATH macros on x86
- increase ZFS EFI partition to 200M
PR: 201898
Reviewed by: allanjude, manu
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D11239