cbfs: add struct cbfsf

Now that cbfs is adding more metadata in the cbfs file
header one needs to access that metadata. Therefore,
add struct cbfsf which tracks the metadata and data
of the file separately. Note that stage and payload
metadata specific to itself is still contained within
the 'data' portion of a cbfs file. Update the cbfs
API to use struct cbfsf. Additionally, remove struct
cbfsd as there's nothing else associated with a cbfs
region aside from offset and size which tracked
by a region_device (thanks, CBFS_ALIGNMENT!).

TEST=Built and booted through end of ramstage on qemu armv7.
     Built and booted glados using Chrome OS.

Change-Id: I05486c6cf6cfcafa5c64b36324833b2374f763c2
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/11679
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
7 files changed