MIPS: BPF: Use 32 or 64-bit load instruction to load an address to register

MIPS: BPF: Use 32 or 64-bit load instruction to load an address to register

When loading a pointer to register we need to use the appropriate
32 or 64bit instruction to preserve the pointers' top 32bits.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.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/7180/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>