misc: chore: Remove redundant code

src/Ryujinx.Horizon/Sdk/Codec/Detail/HardwareOpusDecoderManager.cs

@@ -2,7 +2,6 @@ using Ryujinx.Common;
 using Ryujinx.Horizon.Common;
 using Ryujinx.Horizon.Sdk.Sf;
 using Ryujinx.Horizon.Sdk.Sf.Hipc;
-using System;
 
 namespace Ryujinx.Horizon.Sdk.Codec.Detail
 {

src/Ryujinx.Horizon/Sdk/Ngc/Detail/CompressedArray.cs

@@ -9,20 +9,11 @@ namespace Ryujinx.Horizon.Sdk.Ngc.Detail
         private const int CompressedEntriesPerBlock = 64;
         private const int BitsPerWord = Set.BitsPerWord;
 
-        private readonly struct BitfieldRange
+        private readonly struct BitfieldRange(uint range, int baseValue)
         {
-            private readonly uint _range;
-            private readonly int _baseValue;
-
-            public int BitfieldIndex => (int)(_range & 0x7ffffff);
-            public int BitfieldLength => (int)(_range >> 27) + 1;
-            public int BaseValue => _baseValue;
-
-            public BitfieldRange(uint range, int baseValue)
-            {
-                _range = range;
-                _baseValue = baseValue;
-            }
+            public int BitfieldIndex => (int)(range & 0x7ffffff);
+            public int BitfieldLength => (int)(range >> 27) + 1;
+            public int BaseValue => baseValue;
         }
 
         private uint[] _bitfieldRanges;

src/Ryujinx.Horizon/Sdk/OsTypes/OsEvent.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 using System.Threading;
 
 namespace Ryujinx.Horizon.Sdk.OsTypes