This patch introduces the following prefix convention for the
image format handling and bootm related code:
genimg_ - dual format shared code
image_ - legacy uImage format specific code
fit_ - new uImage format specific code
boot_ - booting process related code
Related routines are renamed and a few pieces of code are moved around and
re-grouped.
Signed-off-by: Marian Balakowicz <m8@semihalf.com>