[PowerPC][CLANG] DMF VSX Vector float GER 2x (rank-2 update) (#147383)
Add clang builtins for DMF VSX Vector floats:
```
void __builtin_mma_dmxvf16gerx2 (__dmr1024 *, __vector_pair, vec_t);
void __builtin_mma_dmxvf16gerx2nn (__dmr1024 *, __vector_pair, vec_t);
void __builtin_mma_dmxvf16gerx2np (__dmr1024 *, __vector_pair, vec_t);
void __builtin_mma_dmxvf16gerx2pn (__dmr1024 *, __vector_pair, vec_t);
void __builtin_mma_dmxvf16gerx2pp (__dmr1024 *, __vector_pair, vec_t);
void __builtin_mma_pmdmxvf16gerx2 (__dmr1024 *, __vector_pair, vec_t, uint8, uint4, uint2);
void __builtin_mma_pmdmxvf16gerx2nn (__dmr1024 *, __vector_pair, vec_t, uint8, uint4, uint2);
void __builtin_mma_pmdmxvf16gerx2np (__dmr1024 *, __vector_pair, vec_t, uint8, uint4, uint2);
void __builtin_mma_pmdmxvf16gerx2pn (__dmr1024 *, __vector_pair, vec_t, uint8, uint4, uint2);
void __builtin_mma_pmdmxvf16gerx2pp (__dmr1024 *, __vector_pair, vec_t, uint8, uint4, uint2);
void __builtin_mma_dmxvbf16gerx2 (__dmr1024 *, __vector_pair, vec_t);
void __builtin_mma_dmxvbf16gerx2nn (__dmr1024 *, __vector_pair, vec_t);
void __builtin_mma_dmxvbf16gerx2np (__dmr1024 *, __vector_pair, vec_t);
void __builtin_mma_dmxvbf16gerx2pn (__dmr1024 *, __vector_pair, vec_t);
void __builtin_mma_dmxvbf16gerx2pp (__dmr1024 *, __vector_pair, vec_t);
void __builtin_mma_pmdmxvbf16gerx2 (__dmr1024 *, __vector_pair, vec_t, uint8, uint4, uint2);
void __builtin_mma_pmdmxvbf16gerx2nn (__dmr1024 *, __vector_pair, vec_t, uint8, uint4, uint2);
void __builtin_mma_pmdmxvbf16gerx2np (__dmr1024 *, __vector_pair, vec_t, uint8, uint4, uint2);
void __builtin_mma_pmdmxvbf16gerx2pn (__dmr1024 *, __vector_pair, vec_t, uint8, uint4, uint2);
void __builtin_mma_pmdmxvbf16gerx2pp (__dmr1024 *, __vector_pair, vec_t, uint8, uint4, uint2);
```