CVE-2024-36918 bpf: Check bloom filter map value size

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

bpf: Check bloom filter map value size

This patch adds a missing check to bloom filter creating, rejecting
values above KMALLOC_MAX_SIZE. This brings the bloom map in line with
many other map types.

The lack of this protection can cause kernel crashes for value sizes
that overflow int’s. Such a crash was caught by syzkaller. The next
patch adds more guard-rails at a lower level.