Misc: Fix a few warnings

pcsx2/Config.h

@@ -1170,10 +1170,7 @@ struct Pcsx2Config
 	// ------------------------------------------------------------------------
 	struct USBOptions
 	{
-		enum : u32
-		{
-			NUM_PORTS = 2
-		};
+		static constexpr u32 NUM_PORTS = 2;
 
 		struct Port
 		{

pcsx2/GS/Renderers/OpenGL/GLShaderCache.cpp

@@ -28,6 +28,7 @@
 #include "common/StringUtil.h"
 #include "common/Timer.h"
 
+namespace {
 #pragma pack(push, 1)
 struct CacheIndexEntry
 {
@@ -42,6 +43,7 @@ struct CacheIndexEntry
 	u32 blob_format;
 };
 #pragma pack(pop)
+}
 
 GLShaderCache::GLShaderCache() = default;
 

pcsx2/GS/Renderers/Vulkan/VKShaderCache.cpp

@@ -44,6 +44,7 @@
 
 std::unique_ptr<VKShaderCache> g_vulkan_shader_cache;
 
+namespace {
 #pragma pack(push, 4)
 struct VK_PIPELINE_CACHE_HEADER
 {
@@ -64,6 +65,7 @@ struct CacheIndexEntry
 	u32 blob_size;
 };
 #pragma pack(pop)
+}
 
 static bool ValidatePipelineCacheHeader(const VK_PIPELINE_CACHE_HEADER& header)
 {

pcsx2/USB/usb-printer/usb-printer.cpp

@@ -29,6 +29,10 @@
 
 namespace usb_printer
 {
+	static const char* sPrinterNames[] = {
+		"Sony DPP-MP1",
+	};
+
 	typedef struct PrinterState
 	{
 		USBDevice dev{};

pcsx2/USB/usb-printer/usb-printer.h

@@ -120,10 +120,6 @@ namespace usb_printer
 		},
 	};
 
-	static const char* sPrinterNames[] = {
-		"Sony DPP-MP1",
-	};
-
 	class PrinterDevice final : public DeviceProxy
 	{
 	public: