mips, bpf: Fix Makefile that referenced a removed file

This patch removes a stale Makefile reference to the cBPF JIT that was
removed.

Fixes: ebcbacfa

 ("mips, bpf: Remove old BPF JIT implementations")
Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211007142339.633899-1-johan.almbladh@anyfinetworks.com