Enable bzipfs support in the EFI loader.
- Add bzipfs to the list of supported filesystems in the EFI loader.
- Increase the heap size allocated for the EFI loader from 2MB to 3MB.
Differential Revision:	https://reviews.freebsd.org/D2053
Reviewed by:	benno, emaste, imp
MFC after:	2 weeks
Sponsored by:	Cisco Systems, Inc.