PowerPC: Create new MMA instruction masks and use them

[Alan Modra]

On Wed, Jul 20, 2022 at 07:01:35PM -0500, Peter Bergner wrote:
> The MMA instructions use XX3_MASK|3<<21 as an instruction mask, but that
> misses the RC bit/bit 31, so if we disassemble a .long that represents an
> MMA instruction except that it also has bit 31 set, we will erroneously
> disassemble it to that MMA instruction.  We create new masks defines that
> contain bit 31 so that doesn't happen anymore.
> 
> This passed testing on powerpc64le-linux with no regressions.
> I plan on pushing this tomorrow unless I hear some objections.

2.39 branch too, please.

-- 
Alan Modra
Australia Development Lab, IBM