aarch64.risu: add LD1, LD2, LD3, LD4 and R forms
aarch64.risu: add LD1, LD2, LD3, LD4 and R forms

    Add the Load Multiple/Single Structure SIMD/fp insns,
    as well as the Replicate forms LD1R, LD2R, LD3R, LD4R.
    Also add the missing stores in the last patch,
    which were mistakenly left out.

Signed-off-by: Claudio Fontana <5fe97b97070bc75ff3c7a6b130e2dcc62cbb9b58@linaro.org>

hw-claudio/risu-aarch64,hw-claudio/risu-aarch64