PPC64: Reduced-Precision: Missing Integer-based Outer Product Operations

PPC64: Reduced-Precision: Missing Integer-based Outer Product Operations

Add support for:

pmxvi16ger2 VSX Vector 16-bit Signed Integer GER (rank-2 update), Prefixed
   Masked
pmxvi16ger2pp VSX Vector 16-bit Signed Integer GER (rank-2 update) (Positive
   multiply, Positive accumulate), Prefixed Masked
pmxvi8ger4spp VSX Vector 8-bit Signed/Unsigned Integer GER (rank-4 update) with
   Saturation (Positive multiply, Positive accumulate), Prefixed Masked
xvi16ger2 VSX Vector 16-bit Signed Integer GER (rank-2 update)
xvi16ger2pp VSX Vector 16-bit Signed Integer GER (rank-2 update) (Positive
   multiply, Positive accumulate)
xvi8ger4spp VSX Vector 8-bit Signed/Unsigned Integer GER (rank-4 update) with
   Saturation (Positive multiply, Positive accumulate)