Fix both the IHEX firmware generation (len field always null, and EOF
marker a byte too short) and loading (struct ihex_binrec needs to be
packed to reflect the on-disk structure).

Signed-off-by: Marc Zyngier <maz@misterjones.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Provide a helper to load the file and validate it in one call, to
simplify error handling in the drivers which are going to use it.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

Some devices need their firmware as a set of {address, len, data...}
records in some specific order rather than a simple blob.

The normal way of doing this kind of thing is 'ihex', which is a text
format and not entirely suitable for use in the kernel.

This provides a binary representation which is very similar, but much
more compact -- and a helper routine to skip to the next record,
because the alignment constraints mean that everybody will screw it up
for themselves otherwise.

Also a helper function which can verify that a 'struct firmware'
contains a valid set of ihex records, and that following them won't run
off the end of the loaded data.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>