bpf, sparc64: remove obsolete exception handling from div/mod

Since we've changed div/mod exception handling for src_reg in
eBPF verifier itself, remove the leftovers from sparc64 JIT.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>