This adds ARMv8 implementations of SM4 in ECB, CBC, CFB and CTR
modes using Crypto Extensions, also includes key expansion operations
because the Crypto Extensions instruction is much faster than software
implementations.

The Crypto Extensions for SM4 can only run on ARMv8 implementations
that have support for these optional extensions.

Benchmark on T-Head Yitian-710 2.75 GHz, the data comes from the 218
mode of tcrypt. The abscissas are blocks of different lengths. The
data is tabulated and the unit is Mb/s:

sm4-generic |     16       64      128      256     1024     1420     4096
    ECB enc |  80.05    91.42    93.66    94.77    95.69    95.77    95.86
    ECB dec |  79.98    91.41    93.64    94.76    95.66    95.77    95.85
    CBC enc |  78.55    86.50    88.02    88.77    89.36    89.42    89.48
    CBC dec |  76.82    89.06    91.52    92.77    93.75    93.83    93.96
    CFB enc |  77.64    86.13    87.62    88.42    89.08    88.83    89.18
    CFB dec |  77.57    88.34    90.36    91.45    92.34    92.00    92.44
    CTR enc |  77.80    88.28    90.23    91.22    92.11    91.81    92.25
    CTR dec |  77.83    88.22    90.22    91.22    92.04    91.82    92.28
sm4-neon
    ECB enc |  28.31   112.77   203.03   209.89   215.49   202.11   210.59
    ECB dec |  28.36   113.45   203.23   210.00   215.52   202.13   210.65
    CBC enc |  79.32    87.02    88.51    89.28    89.85    89.89    89.97
    CBC dec |  28.29   112.20   203.30   209.82   214.99   201.51   209.95
    CFB enc |  79.59    87.16    88.54    89.30    89.83    89.62    89.92
    CFB dec |  28.12   111.05   202.47   209.02   214.21   210.90   209.12
    CTR enc |  28.04   108.81   200.62   206.65   211.78   208.78   206.74
    CTR dec |  28.02   108.82   200.45   206.62   211.78   208.74   206.70
sm4-ce-cipher
    ECB enc | 336.79   587.13   682.70   747.37   803.75   811.52   818.06
    ECB dec | 339.18   584.52   679.72   743.68   798.82   803.83   811.54
    CBC enc | 316.63   521.47   597.00   647.14   690.82   695.21   700.55
    CBC dec | 291.80   503.79   585.66   640.82   689.86   695.16   701.72
    CFB enc | 294.79   482.31   552.13   594.71   631.60   628.91   638.92
    CFB dec | 293.09   466.44   526.56   563.17   594.41   592.26   601.97
    CTR enc | 309.61   506.13   576.86   620.47   656.38   654.51   665.10
    CTR dec | 306.69   505.57   576.84   620.18   657.09   654.52   665.32
sm4-ce
    ECB enc | 366.96  1329.81  2024.29  2755.50  3790.07  3861.91  4051.40
    ECB dec | 367.30  1323.93  2018.72  2747.43  3787.39  3862.55  4052.62
    CBC enc | 358.09   682.68   807.24   885.35   958.29   963.60   973.73
    CBC dec | 366.51  1303.63  1978.64  2667.93  3624.53  3683.41  3856.08
    CFB enc | 351.51   681.26   807.81   893.10   968.54   969.17   985.83
    CFB dec | 354.98  1266.61  1929.63  2634.81  3614.23  3611.59  3841.68
    CTR enc | 324.23  1121.25  1689.44  2256.70  2981.90  3007.79  3060.74
    CTR dec | 324.18  1120.44  1694.31  2258.32  2982.01  3010.09  3060.99
Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>