flash: Rename free_flash_dev to flash_dev_free

Change-Id: I3d3da6312217b6b869fa3f62a1d4752be98fd609
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/test/write_flash.c b/test/write_flash.c
index 4f37bef..f0c107c 100644
--- a/test/write_flash.c
+++ b/test/write_flash.c
@@ -99,7 +99,7 @@
 	rc = memcmp(src, map, sizeof(src));
 	assert(rc == 0);
 
-	free_flash_dev(context);
+	flash_dev_free(context);
 
 	return rc;
 }