md: removing typedefs:  mdk_rdev_t -> struct md_rdev

The typedefs are just annoying. 'mdk' probably refers to 'md_k.h'
which used to be an include file that defined this thing.

Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/faulty.c b/drivers/md/faulty.c
index 23078da..a0fa5a0 100644
--- a/drivers/md/faulty.c
+++ b/drivers/md/faulty.c
@@ -87,7 +87,7 @@
 	sector_t faults[MaxFault];
 	int	modes[MaxFault];
 	int nfaults;
-	mdk_rdev_t *rdev;
+	struct md_rdev *rdev;
 } conf_t;
 
 static int check_mode(conf_t *conf, int mode)
@@ -297,7 +297,7 @@
 
 static int run(mddev_t *mddev)
 {
-	mdk_rdev_t *rdev;
+	struct md_rdev *rdev;
 	int i;
 	conf_t *conf;