MIPS: eBPF: Initial eBPF support for MIPS32 architecture.

MIPS: eBPF: Initial eBPF support for MIPS32 architecture.

Currently MIPS32 supports a JIT for classic BPF only, not extended BPF.
This patch adds JIT support for extended BPF on MIPS32, so code is
actually JIT'ed instead of being only interpreted. Instructions with
64-bit operands are not supported at this point.
We can delete classic BPF because the kernel will translate classic BPF
programs into extended BPF and JIT them, eliminating the need for
classic BPF.

Signed-off-by: Hassan Naveed <[email protected]>
Signed-off-by: Paul Burton <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: Ralf Baechle <[email protected]>
Cc: James Hogan <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: open list:MIPS <[email protected]>
Cc: open list <[email protected]>