core: hle: kernel: svc_common: Add WaitInfinite & cleanup.

src/core/hle/kernel/svc_common.h

@@ -14,8 +14,11 @@ namespace Kernel::Svc {
 
 using namespace Common::Literals;
 
-constexpr s32 ArgumentHandleCountMax = 0x40;
-constexpr u32 HandleWaitMask{1u << 30};
+constexpr inline s32 ArgumentHandleCountMax = 0x40;
+
+constexpr inline u32 HandleWaitMask = 1u << 30;
+
+constexpr inline s64 WaitInfinite = -1;
 
 constexpr inline std::size_t HeapSizeAlignment = 2_MiB;