lib/dma-debug.c: mark file-local struct symbol static.

warning: symbol 'filter_fops' was not declared. Should it be static?

Signed-off-by: Thiago Farina <tfransosi@gmail.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index 7399744..e039958 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -587,7 +587,7 @@
 	return count;
 }
 
-const struct file_operations filter_fops = {
+static const struct file_operations filter_fops = {
 	.read  = filter_read,
 	.write = filter_write,
 };