i7core_edac: fix panic when accessing sysfs files

The i7core_edac addrmatch_dev and chancounts_dev have sysfs files
associated with them.  The sysfs files, however, are coded so that the
parent device is is the mci device.  This is incorrect and the mci struct
should be obtained through the addrmatch_dev and chancounts_dev device's
private data field which is populated in i7core_create_sysfs_devices().

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/edac/i7core_edac.c b/drivers/edac/i7core_edac.c
index 3672101..10c8c00 100644
--- a/drivers/edac/i7core_edac.c
+++ b/drivers/edac/i7core_edac.c
@@ -816,7 +816,7 @@
 	struct device_attribute *mattr,				\
 	const char *data, size_t count)				\
 {								\
-	struct mem_ctl_info *mci = to_mci(dev);			\
+	struct mem_ctl_info *mci = dev_get_drvdata(dev);	\
 	struct i7core_pvt *pvt;					\
 	long value;						\
 	int rc;							\
@@ -845,7 +845,7 @@
 	struct device_attribute *mattr,				\
 	char *data)						\
 {								\
-	struct mem_ctl_info *mci = to_mci(dev);			\
+	struct mem_ctl_info *mci = dev_get_drvdata(dev);	\
 	struct i7core_pvt *pvt;					\
 								\
 	pvt = mci->pvt_info;					\
@@ -1052,7 +1052,7 @@
 	struct device_attribute *mattr,				\
 	char *data)						\
 {								\
-	struct mem_ctl_info *mci = to_mci(dev);			\
+	struct mem_ctl_info *mci = dev_get_drvdata(dev);	\
 	struct i7core_pvt *pvt = mci->pvt_info;			\
 								\
 	edac_dbg(1, "\n");					\