dm: blk: Rename get_device_and_partition()

Rename this function to blk_get_device_part_str(). This is a better name
because it makes it clear that the function returns a block device and
parses a string.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
diff --git a/fs/ubifs/ubifs.c b/fs/ubifs/ubifs.c
index 168ae2b..cdc04c6 100644
--- a/fs/ubifs/ubifs.c
+++ b/fs/ubifs/ubifs.c
@@ -569,7 +569,7 @@
 	}
 
 	/*
-	 * Should never happen since get_device_and_partition() already checks
+	 * Should never happen since blk_get_device_part_str() already checks
 	 * this, but better safe then sorry.
 	 */
 	if (!ubifs_is_mounted()) {