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/rfkill/rfkill.c

@@ -251,10 +251,9 @@ static int load_state(
         l = write(rfkill_fd, &we, sizeof(we));
         if (l < 0)
                 return log_error_errno(errno, "Failed to restore rfkill state for %i: %m", event->idx);
-        if (l != sizeof(we)) {
-                log_error("Couldn't write rfkill event structure, too short.");
-                return -EIO;
-        }
+        if (l != sizeof(we))
+                return log_error_errno(SYNTHETIC_ERRNO(EIO),
+                                       "Couldn't write rfkill event structure, too short.");
 
         log_debug("Loaded state '%s' from %s.", one_zero(b), state_file);
         return 0;