nvdrv: Add MSVC compatibility for packed structs

Add conditional compilation directives to handle packed struct definitions
differently between MSVC and other compilers. MSVC uses #pragma pack
while GCC/Clang use __attribute__((packed)). This change affects:

- ZBCColorEntry
- ZBCDepthEntry
- IoctlZbcSetTable

The functionality remains the same, but ensures proper struct packing
across different compiler environments.

src/core/hle/service/nvdrv/devices/nvhost_ctrl_gpu.h

@@ -45,11 +45,19 @@ private:
 
     struct ZBCColorEntry {
         u32 color_ds[4];
+#ifdef _MSC_VER
+    };
+#else
     } __attribute__((packed));
+#endif
 
     struct ZBCDepthEntry {
         u32 depth[4];
+#ifdef _MSC_VER
+    };
+#else
     } __attribute__((packed));
+#endif
 
     std::array<ZBCColorEntry, MaxZBCTableSize> zbc_color_table{};
     std::array<ZBCDepthEntry, MaxZBCTableSize> zbc_depth_table{};
@@ -139,6 +147,7 @@ private:
     static_assert(sizeof(IoctlNvgpuGpuZcullGetInfoArgs) == 40,
                   "IoctlNvgpuGpuZcullGetInfoArgs is incorrect size");
 
+#ifdef _MSC_VER
 #pragma pack(push, 1)
     struct IoctlZbcSetTable {
         u32 color_ds_table_index;
@@ -147,8 +156,18 @@ private:
         u32 color_ds[4];  // 16 bytes
         u32 color_l2[4];  // 16 bytes
         u32 depth;        // 4 bytes
-    } __attribute__((packed));  // Use GCC's packed attribute
+    };
 #pragma pack(pop)
+#else
+    struct IoctlZbcSetTable {
+        u32 color_ds_table_index;
+        u32 format;
+        u32 mode;
+        u32 color_ds[4];  // 16 bytes
+        u32 color_l2[4];  // 16 bytes
+        u32 depth;        // 4 bytes
+    } __attribute__((packed));
+#endif
 
     static_assert(sizeof(IoctlZbcSetTable) == 48, "IoctlZbcSetTable is incorrect size");