implied: use comparison information for implications

implied: use comparison information for implications

I have wanted to add other sources of implication data for a while.
Comparison is nice for this because smatch_extra implications can't do
anything with it.

Smatch extra handles this:

	if (foo == 5)

Comparison handles this:

	if (foo == end)

Since they don't over lap that makes it simpler.

For now, I have just hard coded the comparison functions into
smatch_implied.c instead of adding hooks.  Eventually I will write proper
hooks for this and handle smatch_conditions.c stuff as well.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>