sw64: bpf: fix ebpf jit compiler

Sunway inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5PNGJ



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This patch makes following changes to ebpf jit compiler:
   * implement proper XADD instructions
   * implement 32-bit ARSH instructions
   * implement DIV and MOD instructions using helper functions
   * reorganize header file to make it easier to read
   * optimize load immediate helper functions
   * make sure ILLEGAL_INSN will throw instruction fault
   * make sure fields in jited instrctions won't overflow
   * restore GP register when exit
   * make sure 32-bit alu functions are unsigned
   * make sure 32-bit results are zero extended to 64 bits
   * make sure function addr are stored in $27 so callee can calculate
     GP correctly
   * track free temporary registers to make sure we won't accidentally
     clobber useful data
   * fix register mapping
   * fix host to be algorithm
   * fix offset calculation of branch instructions
   * fix tail call

Result of "test_bpf.ko": 378 PASSED, 0 FAILED, [366/366 JIT'ed]

Signed-off-by: Mao Minkai <maominkai@wxiat.com>
Signed-off-by: Gu Zitao <guzitao@wxiat.com>