kernel/panic.c: display reason at end + pr_emerg

Currently, booting without initrd specified on 80x25 screen gives a call
trace followed by atkbd : Spurious ACK. Original message ("VFS: Unable
to mount root fs") is not available. Of course this could happen in
other situations...

This patch displays panic reason after call trace which could help lot
of people even if it's not the very last line on screen.

Also, convert all panic.c printk(KERN_EMERG to pr_emerg(

[[e-mail]: missed a couple of pr_ conversions]
Signed-off-by: Fabian Frederick <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

kernel/panic.c

···
 	va_start(args, fmt);
 	vsnprintf(buf, sizeof(buf), fmt, args);
 	va_end(args);
-	printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf);
+	pr_emerg("Kernel panic - not syncing: %s\n", buf);
 #ifdef CONFIG_DEBUG_BUGVERBOSE
 	/*
 	 * Avoid nested stack-dumping if a panic occurs during oops processing
···
 		 * Delay timeout seconds before rebooting the machine.
 		 * We can't use the "normal" timers since we just panicked.
 		 */
-		printk(KERN_EMERG "Rebooting in %d seconds..", panic_timeout);
+		pr_emerg("Rebooting in %d seconds..", panic_timeout);
 
 		for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP) {
 			touch_nmi_watchdog();
···
 		extern int stop_a_enabled;
 		/* Make sure the user can actually press Stop-A (L1-A) */
 		stop_a_enabled = 1;
-		printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n");
+		pr_emerg("Press Stop-A (L1-A) to return to the boot prom\n");
 	}
 #endif
 #if defined(CONFIG_S390)
···
 		disabled_wait(caller);
 	}
 #endif
+	pr_emerg("---[ end Kernel panic - not syncing: %s\n", buf);
 	local_irq_enable();
 	for (i = 0; ; i += PANIC_TIMER_STEP) {
 		touch_softlockup_watchdog();
···
 void add_taint(unsigned flag, enum lockdep_ok lockdep_ok)
 {
 	if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off())
-		printk(KERN_WARNING
-		       "Disabling lock debugging due to kernel taint\n");
+		pr_warn("Disabling lock debugging due to kernel taint\n");
 
 	set_bit(flag, &tainted_mask);
 }
···
 void print_oops_end_marker(void)
 {
 	init_oops_id();
-	printk(KERN_WARNING "---[ end trace %016llx ]---\n",
-		(unsigned long long)oops_id);
+	pr_warn("---[ end trace %016llx ]---\n", (unsigned long long)oops_id);
 }
 
 /*