UBUNTU: SAUCE: (no-up) Convert bnx2x firmware files to ihex format

The Makefile system thinks the .fw files are generated targets so it wants
to clean them.  Keep them as ascii .ihex files instead (like the rest).
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>