crypto: arm64/sm4 - refactor and simplify NEON implementation

This patch does not add new features. The main work is to refactor and
simplify the implementation of SM4 NEON, which is reflected in the
following aspects:

The accelerated implementation supports the arbitrary number of blocks,
not just multiples of 8, which simplifies the implementation and brings
some optimization acceleration for data that is not aligned by 8 blocks.

When loading the input data, use the ld4 instruction to replace the
original ld1 instruction as much as possible, which will save the cost
of matrix transposition of the input data.

Use 8-block parallelism whenever possible to speed up matrix transpose
and rotation operations, instead of up to 4-block parallelism.

Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>