Update ymfm to latest upstream

src/sound/ymfm/ymfm_opl.cpp

@@ -100,6 +100,11 @@ opl_registers_base<Revision>::opl_registers_base() :
 			}
 		}
 	}
+
+	// OPL3/OPL4 have dynamic operators, so initialize the fourop_enable value here
+	// since operator_map() is called right away, prior to reset()
+	if (Revision > 2)
+		m_regdata[0x104 % REGISTERS] = 0;
 }
 
 
@@ -1710,9 +1715,15 @@ uint8_t ymf278b::read_status()
 
 uint8_t ymf278b::read_data_pcm()
 {
-	// write to FM
+	// read from PCM
 	if (bitfield(m_address, 9) != 0)
-		return m_pcm.read(m_address & 0xff);
+	{
+		uint8_t result = m_pcm.read(m_address & 0xff);
+		if ((m_address & 0xff) == 0x02)
+			result |= 0x20;
+
+		return result;
+	}
 	return 0;
 }