Make structs readonly when applicable (#4002)

* Make all structs readonly when applicable. It should reduce amount of needless defensive copies

* Make structs with trivial boilerplate equality code record structs

* Remove unnecessary readonly modifiers from TextureCreateInfo

* Make BitMap structs readonly too

Ryujinx.Graphics.Gpu/Image/FormatInfo.cs

@@ -5,7 +5,7 @@ namespace Ryujinx.Graphics.Gpu.Image
     /// <summary>
     /// Represents texture format information.
     /// </summary>
-    struct FormatInfo
+    readonly struct FormatInfo
     {
         /// <summary>
         /// A default, generic RGBA8 texture format.

Ryujinx.Graphics.Gpu/Image/TextureBindingInfo.cs

@@ -7,7 +7,7 @@ namespace Ryujinx.Graphics.Gpu.Image
     /// Texture binding information.
     /// This is used for textures that needs to be accessed from shaders.
     /// </summary>
-    struct TextureBindingInfo
+    readonly struct TextureBindingInfo
     {
         /// <summary>
         /// Shader sampler target type.

Ryujinx.Graphics.Gpu/Image/TextureCache.cs

@@ -16,7 +16,7 @@ namespace Ryujinx.Graphics.Gpu.Image
     /// </summary>
     class TextureCache : IDisposable
     {
-        private struct OverlapInfo
+        private readonly struct OverlapInfo
         {
             public TextureViewCompatibility Compatibility { get; }
             public int FirstLayer { get; }

Ryujinx.Graphics.Gpu/Image/TextureGroup.cs

@@ -14,7 +14,7 @@ namespace Ryujinx.Graphics.Gpu.Image
     /// <summary>
     /// An overlapping texture group with a given view compatibility.
     /// </summary>
-    struct TextureIncompatibleOverlap
+    readonly struct TextureIncompatibleOverlap
     {
         public readonly TextureGroup Group;
         public readonly TextureViewCompatibility Compatibility;

Ryujinx.Graphics.Gpu/Image/TextureInfo.cs

@@ -6,7 +6,7 @@ namespace Ryujinx.Graphics.Gpu.Image
     /// <summary>
     /// Texture information.
     /// </summary>
-    struct TextureInfo
+    readonly struct TextureInfo
     {
         /// <summary>
         /// Address of the texture in GPU mapped memory.