block: IBM RamSan 70/80 driver fixes

This patch includes the following driver fixes for the
IBM RamSan 70/80 driver:

o Changed the creg_ctrl lock from a mutex to a spinlock.
o Added a count check for ioctl calls.
o Removed unnecessary casting of void pointers.
o Made every function static that needed to be.
o Added comments to explain things more thoroughly.

Signed-off-by: Philip J Kelleher <pjk1939@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/drivers/block/rsxx/config.c b/drivers/block/rsxx/config.c
index c8829cd..a295e7e 100644
--- a/drivers/block/rsxx/config.c
+++ b/drivers/block/rsxx/config.c
@@ -31,7 +31,7 @@
 
 static void initialize_config(void *config)
 {
-	struct rsxx_card_cfg *cfg = (struct rsxx_card_cfg *) config;
+	struct rsxx_card_cfg *cfg = config;
 
 	cfg->hdr.version = RSXX_CFG_VERSION;
 
@@ -97,7 +97,7 @@
 
 
 /*----------------- Config Operations ------------------*/
-int rsxx_save_config(struct rsxx_cardinfo *card)
+static int rsxx_save_config(struct rsxx_cardinfo *card)
 {
 	struct rsxx_card_cfg cfg;
 	int st;