[AMDGPU] Add IsSingle to V_DIV_FMAS* for consistency. (llvm#95983)

A _e64 suffix should not be printed since these instructions only have
one legal encoding length. The absence of the IsSingle flag is hidden by
how the string is printed, but fix it for consistency.
NFC

Author: Sisyph

llvm/lib/Target/AMDGPU/VOP3Instructions.td

@@ -13,9 +13,11 @@ def VOP_F32_F32_F32_F32_VCC : VOPProfile<[f32, f32, f32, f32]> {
   let Outs64 = (outs DstRC.RegClass:$vdst);
   let HasExtVOP3DPP = 0;
   let HasExtDPP = 0;
+  let IsSingle = 1;
 }
 def VOP_F64_F64_F64_F64_VCC : VOPProfile<[f64, f64, f64, f64]> {
   let Outs64 = (outs DstRC.RegClass:$vdst);
+  let IsSingle = 1;
 }
 }