[Libre-soc-dev] mv.zip and mv.unzip (vector pack and unpack)

[lkcl]

https://libre-soc.org/openpower/sv/mv.swizzle/

likewise mv.swizzle, these are so expensive, they barely fit.  the original plan was to propose them for EXT019 but they would have taken up EIGHT columns in one of the EXT019 quadrants. i did a quick check yesterday, there are only around 50 such 32-entry columns in the whole of Power ISA, some in EXT031, some in EXT019, others as well, they are a really precious resource.

i moved them to the EXT022 Sandbox as one of the highest-cost operations, a peer of grevlut etc.

interestingly the MV-RM prefix form giving a src vec2 separate from dest vec2 would fit, which leaves room for some interesting possibilities.