mmc: Flush pending detects on host removal

Make sure we kill of any pending detection runs when the host
is removed instead of when it is freed. Also add some debugging
to make sure the driver doesn't queue up more detection after it
has removed the host.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

include/linux/mmc/host.h

@@ -147,6 +147,9 @@ struct mmc_host {
 	struct mmc_card		*card_selected;	/* the selected MMC card */
 
 	struct delayed_work	detect;
+#ifdef CONFIG_MMC_DEBUG
+	unsigned int		removed:1;	/* host is being removed */
+#endif
 
 	unsigned long		private[0] ____cacheline_aligned;
 };