nak: s/HashSet::new()/Default::default()/

wherever this doesn't result in type inference failing.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34865>

src/nouveau/compiler/nak/assign_regs.rs

@@ -18,7 +18,7 @@ struct KillSet {
 impl KillSet {
     pub fn new() -> KillSet {
         KillSet {
-            set: HashSet::new(),
+            set: Default::default(),
             vec: Vec::new(),
         }
     }

src/nouveau/compiler/nak/calc_instr_deps.rs

@@ -76,7 +76,7 @@ impl DepGraph {
             deps: Vec::new(),
             instr_deps: Default::default(),
             instr_waits: Default::default(),
-            active: HashSet::new(),
+            active: Default::default(),
         }
     }
 

src/nouveau/compiler/nak/from_nir.rs

@@ -347,12 +347,12 @@ impl<'a> ShaderFromNir<'a> {
             label_alloc: LabelAllocator::new(),
             block_label: Default::default(),
             bar_label: Default::default(),
-            sync_blocks: HashSet::new(),
+            sync_blocks: Default::default(),
             crs: Vec::new(),
             fs_out_regs: [None; 34],
             end_block_id: 0,
             ssa_map: Default::default(),
-            saturated: HashSet::new(),
+            saturated: Default::default(),
             nir_instr_printer: NirInstrPrinter::new().unwrap(),
         }
     }

src/nouveau/compiler/nak/liveness.rs

@@ -18,7 +18,7 @@ impl LiveSet {
     pub fn new() -> LiveSet {
         LiveSet {
             live: Default::default(),
-            set: HashSet::new(),
+            set: Default::default(),
         }
     }
 

src/nouveau/compiler/nak/opt_dce.rs

@@ -20,8 +20,8 @@ impl DeadCodePass {
         DeadCodePass {
             any_dead: false,
             new_live: false,
-            live_ssa: HashSet::new(),
-            live_phi: HashSet::new(),
+            live_ssa: Default::default(),
+            live_phi: Default::default(),
         }
     }