USB: ezusb: add functions for firmware download

This patch adds new functions to upload firmware to the controller. The
drivers currently using ezusb are adapted to use these new functions.

This also fixes a bug occuring during firmware loading in the
whiteheat-driver:
The driver iterates over an ihex-formatted firmware using ++ on a "const
struct ihex_binrec*" which leads to faulty results, because ihex data is
read as length. The function "ihex_next_binrec(record)" has so be used
to work correctly

Signed-off-by: René Bürgel <rene.buergel@sohard.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>