fsconfig: Use defined macro for masking

Mask opeation with CAP_ prefixed name can be wrapped with
CAP_MASK_LONG macro.

Change-Id: Ide31ad62fac0d28e7a02e45059fe6d2461da7e27
diff --git a/tools/fs_config/fs_config_generator.py b/tools/fs_config/fs_config_generator.py
index 2cf2fd8..c8d1dd3 100755
--- a/tools/fs_config/fs_config_generator.py
+++ b/tools/fs_config/fs_config_generator.py
@@ -709,7 +709,7 @@
                 int(cap, 0)
                 tmp.append('(' + cap + ')')
             except ValueError:
-                tmp.append('(1ULL << CAP_' + cap.upper() + ')')
+                tmp.append('CAP_MASK_LONG(CAP_' + cap.upper() + ')')
 
         caps = tmp