[MLIR][NVVM] Fix predicate operand index in BasicPtxBuilderInterface (#189552)
Predicate index computation was incorrect, it was not counting
write/readwrite symbols.
Wrong case
```
// CHECK: %{{.*}} = llvm.inline_asm has_side_effects asm_dialect = att "@$1 ex2.approx.ftz.f32 $0, $1;", "=f,f,b" %{{.*}}, %{{.*}} : (f32, i1) -> f32
%1 = nvvm.inline_ptx "ex2.approx.ftz.f32 {$w0}, {$r0};" ro (%input : f32), predicate = %pred -> f32
```
PR fixes, predicate index became `@$2`
```
// CHECK: %{{.*}} = llvm.inline_asm has_side_effects asm_dialect = att "@$2 ex2.approx.ftz.f32 $0, $1;", "=f,f,b" %{{.*}}, %{{.*}} : (f32, i1) -> f32
%1 = nvvm.inline_ptx "ex2.approx.ftz.f32 {$w0}, {$r0};" ro (%input : f32), predicate = %pred -> f32
```
97b78d6ff3