bpf: add new insns for bswap_to_le and negation

This patch adds new insn, "reg = be16/be32/be64 reg",
for bswap to little endian for big-endian target (bpfeb).
It also adds new insn for negation "reg = -reg".

Currently, for source code, e.g.,
  b = -a
LLVM still prefers to generate:
  b = 0 - a
But "reg = -reg" format can be used in assembly code.

Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314376 91177308-0d34-0410-b5e6-96231b3b80d8
7 files changed