resource: Add resource_contains()

We have two identical copies of resource_contains() already, and more
places that could use it.  This moves it to ioport.h where it can be
shared.

resource_contains(struct resource *r1, struct resource *r2) returns true
iff r1 and r2 are the same type (most callers already checked this
separately) and the r1 address range completely contains r2.

In addition, the new resource_contains() checks that both r1 and r2 have
addresses assigned to them.  If a resource is IORESOURCE_UNSET, it doesn't
have a valid address and can't contain or be contained by another resource.
Some callers already check this or for res->start.

No functional change.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>