coccinelle: make use of SYNTHETIC_ERRNO

Ideally, coccinelle would strip unnecessary braces too. But I do not see any
option in coccinelle for this, so instead, I edited the patch text using
search&replace to remove the braces. Unfortunately this is not fully automatic,
in particular it didn't deal well with if-else-if-else blocks and ifdefs, so
there is an increased likelikehood be some bugs in such spots.

I also removed part of the patch that coccinelle generated for udev, where we
returns -1 for failure. This should be fixed independently.

src/basic/cgroup-util.c

@@ -2545,11 +2545,10 @@ static int cg_unified_update(void) {
                                 unified_cache = CGROUP_UNIFIED_NONE;
                         }
                 }
-        } else {
-                log_debug("Unknown filesystem type %llx mounted on /sys/fs/cgroup.",
-                          (unsigned long long) fs.f_type);
-                return -ENOMEDIUM;
-        }
+        } else
+                return log_debug_errno(SYNTHETIC_ERRNO(ENOMEDIUM),
+                                       "Unknown filesystem type %llx mounted on /sys/fs/cgroup.",
+                                       (unsigned long long)fs.f_type);
 
         return 0;
 }