decode/texture: Resolve unused variable warnings.

Some variables aren't used, so we can remove these.

Unfortunately, diagnostics are still reported on structured bindings
even when annotated with [[maybe_unused]], so we need to unpack the
elements that we want to use manually.

src/video_core/shader/decode/texture.cpp

@@ -268,7 +268,6 @@ u32 ShaderIR::DecodeTexture(NodeBlock& bb, u32 pc) {
                              "NDV is not implemented");
 
         auto texture_type = instr.tmml.texture_type.Value();
-        const bool is_array = instr.tmml.array != 0;
         Node index_var{};
         const Sampler* sampler =
             is_bindless ? GetBindlessSampler(instr.gpr20, index_var) : GetSampler(instr.sampler);
@@ -592,8 +591,9 @@ Node4 ShaderIR::GetTexCode(Instruction instr, TextureType texture_type,
         ++parameter_register;
     }
 
-    const auto [coord_count, total_coord_count] = ValidateAndGetCoordinateElement(
-        texture_type, depth_compare, is_array, lod_bias_enabled, 4, 5);
+    const auto coord_counts = ValidateAndGetCoordinateElement(texture_type, depth_compare, is_array,
+                                                              lod_bias_enabled, 4, 5);
+    const auto coord_count = std::get<0>(coord_counts);
     // If enabled arrays index is always stored in the gpr8 field
     const u64 array_register = instr.gpr8.Value();
     // First coordinate index is the gpr8 or gpr8 + 1 when arrays are used
@@ -631,8 +631,10 @@ Node4 ShaderIR::GetTexsCode(Instruction instr, TextureType texture_type,
     const bool lod_bias_enabled =
         (process_mode != TextureProcessMode::None && process_mode != TextureProcessMode::LZ);
 
-    const auto [coord_count, total_coord_count] = ValidateAndGetCoordinateElement(
-        texture_type, depth_compare, is_array, lod_bias_enabled, 4, 4);
+    const auto coord_counts = ValidateAndGetCoordinateElement(texture_type, depth_compare, is_array,
+                                                              lod_bias_enabled, 4, 4);
+    const auto coord_count = std::get<0>(coord_counts);
+
     // If enabled arrays index is always stored in the gpr8 field
     const u64 array_register = instr.gpr8.Value();
     // First coordinate index is stored in gpr8 field or (gpr8 + 1) when arrays are used