board: gdsys: Configure DP501 SPDIF input

Signed-off-by: Dirk Eibach <dirk.eibach@gdsys.cc>
Reviewed-by: Heiko Schocher <hs@denx.de>
diff --git a/board/gdsys/common/dp501.c b/board/gdsys/common/dp501.c
index 7eb15ed..baace38 100644
--- a/board/gdsys/common/dp501.c
+++ b/board/gdsys/common/dp501.c
@@ -77,6 +77,8 @@
 	i2c_reg_write(addr + 2, 0x24, 0x02); /* clock input single ended */
 #endif
 
+	i2c_reg_write(addr + 2, 0x1a, 0x04); /* SPDIF input method TTL */
+
 	i2c_reg_write(addr + 2, 0x00, 0x18); /* driving strength */
 	i2c_reg_write(addr + 2, 0x03, 0x06); /* driving strength */
 	i2c_reg_write(addr, 0x2c, 0x00); /* configure N value */