[Hexagon] Fix HWBF16 PatLeaf type

Correct the definition of `HWBF16` to reference `VecPBF16`
rather than `VecBF16`, aligning it with the existing
pattern-leaf conventions for pointer vector types.

Author: fhossein-quic

llvm/lib/Target/Hexagon/HexagonPatternsHVX.td

@@ -22,7 +22,7 @@ def HWI16:  PatLeaf<(VecPI16 HvxWR:$R)>;
 def HWI32:  PatLeaf<(VecPI32 HvxWR:$R)>;
 def HWF16:  PatLeaf<(VecPF16 HvxWR:$R)>;
 def HWF32:  PatLeaf<(VecPF32 HvxWR:$R)>;
-def HWBF16: PatLeaf<(VecBF16 HvxWR:$R)>;
+def HWBF16: PatLeaf<(VecPBF16 HvxWR:$R)>;
 
 def SDTVecUnaryOp:
   SDTypeProfile<1, 1, [SDTCisVec<0>, SDTCisVec<1>]>;