minor optimization for FIFO_control::read_put() (#6768)

rpcs3/Emu/RSX/RSXFIFO.cpp

@@ -31,17 +31,25 @@ namespace rsx
 		}
 
 		template <bool full>
-		u32 FIFO_control::read_put()
+		inline u32 FIFO_control::read_put()
 		{
 			if constexpr (!full)
 			{
 				return m_ctrl->put & ~3;
 			}
 			else
+			{
+				u32 put = m_ctrl->put;
+				if (LIKELY((put & 3) == 0))
+				{
+					return put;
+				}
+				else
 				{
 					return m_ctrl->put.and_fetch(~3);
 				}
 			}
+		}
 
 		void FIFO_control::set_put(u32 put)
 		{