entry: Unbreak single step reporting behaviour

The move of TIF_SYSCALL_EMU to SYSCALL_WORK_SYSCALL_EMU broke single step
reporting. The original code reported the single step when TIF_SINGLESTEP
was set and TIF_SYSCALL_EMU was not set. The SYSCALL_WORK conversion got
the logic wrong and now the reporting only happens when both bits are set.

Restore the original behaviour.

[ tglx: Massaged changelog and dropped the pointless double negation ]

Fixes: 64eb35f ("ptrace: Migrate TIF_SYSCALL_EMU to use SYSCALL_WORK flag")
Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Link: https://lore.kernel.org/r/877do3gaq9.fsf@m5Zedd9JOGzJrf0

Author: yshui

kernel/entry/common.c

@@ -222,7 +222,7 @@ static inline bool report_single_step(unsigned long work)
  */
 static inline bool report_single_step(unsigned long work)
 {
-	if (!(work & SYSCALL_WORK_SYSCALL_EMU))
+	if (work & SYSCALL_WORK_SYSCALL_EMU)
 		return false;
 
 	return !!(current_thread_info()->flags & _TIF_SINGLESTEP);