MIPS: bpf: Fix is_range() semantics

MIPS: bpf: Fix is_range() semantics

is_range() was meant to check whether the number is within
the s16 range or not. However the return values and consumers expected
the exact opposite. We fix that by inverting the logic in the function
to return 'true' for < s16 and 'false' for > s16.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Reported-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: netdev@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7131/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>