CVE-2022-48938 CDC-NCM: avoid overflow in sanity checking

In the Linux kernel, the following vulnerability has been resolved:

CDC-NCM: avoid overflow in sanity checking

A broken device may give an extreme offset like 0xFFF0
and a reasonable length for a fragment. In the sanity
check as formulated now, this will create an integer
overflow, defeating the sanity check. Both offset
and offset + len need to be checked in such a manner
that no overflow can occur.
And those quantities should be unsigned.