um: Remove outdated asm/sysrq.h header

This header no longer serves a purpose after show_trace was removed
by commit 9d1ee8ce ("um: Rewrite show_stack()").
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

arch/um/include/asm/sysrq.h

-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __UM_SYSRQ_H
-#define __UM_SYSRQ_H
-
-struct task_struct;
-extern void show_trace(struct task_struct* task, unsigned long *stack);
-
-#endif

arch/um/kernel/sysrq.c

@@ -11,7 +11,6 @@
 #include <linux/sched/debug.h>
 #include <linux/sched/task_stack.h>
 
-#include <asm/sysrq.h>
 #include <asm/stacktrace.h>
 #include <os.h>
 

arch/x86/um/sysrq_32.c

@@ -9,7 +9,6 @@
 #include <linux/sched/debug.h>
 #include <linux/kallsyms.h>
 #include <asm/ptrace.h>
-#include <asm/sysrq.h>
 
 /* This is declared by <linux/sched.h> */
 void show_regs(struct pt_regs *regs)

arch/x86/um/sysrq_64.c

@@ -12,7 +12,6 @@
 #include <linux/utsname.h>
 #include <asm/current.h>
 #include <asm/ptrace.h>
-#include <asm/sysrq.h>
 
 void show_regs(struct pt_regs *regs)
 {