Add support of superio sch4304. 

The datasheet of the sch4304 doesnt seems to be public. So the patch
should not be based on the information got from datasheet. Here is
the result of superiotool.

bash# ./superiotool
superiotool r4931
Found SMSC SCH4307 (id=0x90, rev=0x03) at 0x2e

So we can know the Device id is 0x90. The sub-devices which I enabled are
the ones whose LDNs don't change at all. So I believe it doesn't hurt anyone.

I have not get the board to test it. I will have one. But I believe it is
right, isn't it?


Signed-off-by: Zheng Bao <zheng.bao@amd.com>


Index: src/superio/smsc/smscsuperio/superio.c
===================================================================
--- src/superio/smsc/smscsuperio/superio.c	(revision 4967)
+++ src/superio/smsc/smscsuperio/superio.c	(working copy)
@@ -61,6 +61,7 @@
 #define SCH3112		0x7c
 #define SCH5307		0x81	/* Rebranded LPC47B397(?) */
 #define SCH5027D	0x89
+#define SCH4304		0x90	/* SCH4304, SCH4307 */
 
 /* Register defines */
 #define DEVICE_ID_REG	0x20	/* Device ID register */
@@ -137,6 +138,7 @@
 	{SCH3112,  {0, 3, 4,  5, -1,  7, -1,  -1, -1,  -1, -1, -1, 10, -1, -1}},
 	{SCH5307,  {0, 3, 4,  5, -1,  7, -1,  -1,  8,  -1, -1, -1, 10, -1, -1}},
 	{SCH5027D, {0, 3, 4,  5, -1,  7, -1,  -1, -1,  -1, -1, -1, 10, -1, 11}},
+	{SCH4304,  {0,-1, 4, -1, -1,  7, -1,  -1, -1,  -1, -1, -1, -1, -1, -1}},
 };
 
 /**