aarch64.risu: add C3.6.6 AdvSIMD modified immediate
aarch64.risu: add C3.6.6 AdvSIMD modified immediate

this adds C3.6.6, including

MOVI, ORR (vector, immediate), FMOV (vector, immediate),
MVNI, BIC (vector, immediate)

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

stsquad/risu,stsquad/risu,stsquad/risu,vivier/risu,vivier/risu