mas_writereg() was broken


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@1109 a1c6a512-1295-4272-9138-f99709370657
diff --git a/firmware/drivers/mas.c b/firmware/drivers/mas.c
index e858748..86a188d 100644
--- a/firmware/drivers/mas.c
+++ b/firmware/drivers/mas.c
@@ -166,7 +166,7 @@
 
     i=0;
     buf[i++] = MAS_DATA_WRITE;
-    buf[i++] = MAS_CMD_READ_REG | (reg >> 4);
+    buf[i++] = MAS_CMD_WRITE_REG | (reg >> 4);
     buf[i++] = ((reg & 0x0f) << 4) | (val & 0x0f);
     buf[i++] = (val >> 12) & 0xff;
     buf[i++] = (val >> 4) & 0xff;