Add class / device portability code. Two autoconf tests

were added to cover the 3 possible APIs from 2.6.9 to
2.6.26.  We attempt to use the newest interfaces and if
not available fallback to the oldest.  This a rework of
some changes proposed by Ricardo for RHEL4.



git-svn-id: https://outreach.scidac.gov/svn/spl/trunk@150 7e1ea52c-4ff2-0310-8f11-9dd32ca42a1c

include/sys/sunddi.h

@@ -35,7 +35,7 @@
 #include <linux/fs.h>
 #include <linux/cdev.h>
 #include <linux/list.h>
-#include <linux/device.h>
+#include <spl-device.h>
 
 typedef int ddi_devid_t;
 
@@ -81,7 +81,7 @@ typedef struct dev_info {
 	kmutex_t di_lock;
 	struct dev_ops *di_ops;
 	struct cdev *di_cdev;
-	struct class *di_class;
+	spl_class *di_class;
 	major_t	di_major;
 	minor_t di_minor;
 	dev_t di_dev;