gpu: ion: Use correct type for variables

Use correct type for variables to prevent overflow of signed
type when assiging from an unsigned type.

Change-Id: I0055d35c7310d111de590db3798950fd98f1b298
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
diff --git a/drivers/gpu/ion/ion_system_heap.c b/drivers/gpu/ion/ion_system_heap.c
index 163c1dc..02f6d93 100644
--- a/drivers/gpu/ion/ion_system_heap.c
+++ b/drivers/gpu/ion/ion_system_heap.c
@@ -161,7 +161,7 @@
 	struct list_head pages;
 	struct page_info *info, *tmp_info;
 	int i = 0;
-	long size_remaining = PAGE_ALIGN(size);
+	unsigned long size_remaining = PAGE_ALIGN(size);
 	unsigned int max_order = orders[0];
 	bool split_pages = ion_buffer_fault_user_mappings(buffer);