aacraid: Fix character device re-initialization

During EEH PCI hotplug activity kernel unloads and loads the driver,
causing character device to be unregistered(aac_remove_one).When the
driver is loaded back using aac_probe_one the character device needs
to be registered again for the AIF management tools to work.

Fixed by adding code to register character device in aac_probe_one if
it is unregistered in aac_remove_one.

Signed-off-by: Raghava Aditya Renukunta <raghavaaditya.renukunta@pmcs.com>
Reviewed-by: Shane Seymour <shane.seymour@hpe.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/drivers/scsi/aacraid/aacraid.h b/drivers/scsi/aacraid/aacraid.h
index 75bc65e..9cdf4d2 100644
--- a/drivers/scsi/aacraid/aacraid.h
+++ b/drivers/scsi/aacraid/aacraid.h
@@ -94,6 +94,13 @@
 #define aac_phys_to_logical(x)  ((x)+1)
 #define aac_logical_to_phys(x)  ((x)?(x)-1:0)
 
+/*
+ * These macros are for keeping track of
+ * character device state.
+ */
+#define AAC_CHARDEV_UNREGISTERED	(-1)
+#define AAC_CHARDEV_NEEDS_REINIT	(-2)
+
 /* #define AAC_DETAILED_STATUS_INFO */
 
 struct diskparm