nvmem: core: fix error path in nvmem_add_cells()

The current code fails to nvmem_cell_drop(cells[0]) - even worse, if
the loop above fails already at i==0, we'll enter an essentially
infinite loop doing nvmem_cell_drop on cells[-1], cells[-2], ... which
is unlikely to end well.

Also, we're not freeing the temporary backing array cells on the error
path.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/nvmem/core.c

@@ -294,9 +294,11 @@ static int nvmem_add_cells(struct nvmem_device *nvmem,
 
 	return 0;
 err:
-	while (--i)
+	while (i--)
 		nvmem_cell_drop(cells[i]);
 
+	kfree(cells);
+
 	return rval;
 }