Freezer: fix more fallout from the thaw_process rename

Commit 944e192db53c "freezer: rename thaw_process() to __thaw_task()
and simplify the implementation" did not create a !CONFIG_FREEZER version
of __thaw_task().

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

include/linux/freezer.h

@@ -149,6 +149,7 @@ static inline int freezer_should_skip(struct task_struct *p)
 #else /* !CONFIG_FREEZER */
 static inline bool frozen(struct task_struct *p) { return false; }
 static inline bool freezing(struct task_struct *p) { return false; }
+static inline void __thaw_task(struct task_struct *t) {}
 
 static inline bool __refrigerator(bool check_kthr_stop) { return false; }
 static inline int freeze_processes(void) { return -ENOSYS; }