ADDHA/ADDVA ZAda.S, Pn/m, Pm/m, Zn.S via a new ZA_TILE_LOW encoding
(accumulator tile at bits 2:0; Pn at 12:10, Pm at 15:13, Zn at 9:5).
Byte-exact vs llvm-mc and decode-clean across tile/predicate/Zn fields.
The other 11 missing SME enum names (SME_LD1*/ST1*_ZA, SME_MOVA_TO_Z/ZA)
are redundant aliases of the already-implemented SME_LD1*/ST1*_TILE and
SME_MOVA_*_FROM_* forms -- adding duplicate encodings collides in the
decode table (broke a roundtrip test), so they are intentionally left to
the existing canonical forms. 461 tests green.
69157b7ec5