tree-wide: move unsigned to the start of type declaration

Even though ISO C11 doesn't mandate in which order the type specifiers
should appear, having `unsigned` at the beginning of each type
declaration feels more natural and, more importantly, it unbreaks
Coccinelle, which has a hard time parsing `long unsigned` and others:

```
init_defs_builtins: /usr/lib64/coccinelle/standard.h
init_defs: /home/mrc0mmand/repos/systemd/coccinelle/macros.h
HANDLING: src/shared/mount-util.c
: 1: strange type1, maybe because of weird order: long unsigned
```

Most of the codebase already "complies", so let's fix the remaining
"offenders".

src/shared/mount-util.c

@@ -592,9 +592,9 @@ int mode_to_inaccessible_node(
         return 0;
 }
 
-int mount_flags_to_string(long unsigned flags, char **ret) {
+int mount_flags_to_string(unsigned long flags, char **ret) {
         static const struct {
-                long unsigned flag;
+                unsigned long flag;
                 const char *name;
         } map[] = {
                 { .flag = MS_RDONLY,      .name = "MS_RDONLY",      },

src/shared/mount-util.h

@@ -94,7 +94,7 @@ int mount_option_mangle(
                 char **ret_remaining_options);
 
 int mode_to_inaccessible_node(const char *runtime_dir, mode_t mode, char **dest);
-int mount_flags_to_string(long unsigned flags, char **ret);
+int mount_flags_to_string(unsigned long flags, char **ret);
 
 /* Useful for usage with _cleanup_(), unmounts, removes a directory and frees the pointer */
 static inline char* umount_and_rmdir_and_free(char *p) {