Now that the other architecture-specific lib directories have been
moved out of the top-level directory there's not much reason to have the
'_generic' suffix on the common lib directory.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>

According to the PPC reference implementation the udelay() function is
responsible for resetting the watchdog timer as frequently as needed.
Most other architectures do not meet that requirement, so long-running
operations might result in a watchdog reset.

This patch adds a generic udelay() function which takes care of
resetting the watchdog before calling an architecture-specific
__udelay().

Signed-off-by: Ingo van Lil <inguin@gmx.de>

Also add a rule to remove demo.bin which was previously leftover
after a "make clean"

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>