mmc: Add support for update/delete hostfw

The hostfw image file can be delivered in the code update
tarball. If it is, then update it (copy the file to the
hostfw partition directory.

To delete it, need to first unmount the secondary (non-
running) hostfw mount, then delete the file.

Change-Id: I352dd017114d58b79f9e624983841eafce5badf1
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
2 files changed