panic: call console_verbose() in panic

Most distros turn the console verbosity down and that means a backtrace
after a panic never makes it to the console. I assume we haven't seen
this because a panic is often preceeded by an oops which will have called
console_verbose. There are however a lot of places we call panic
directly, and they are broken.

Use console_verbose like we do in the oops path to ensure a directly
called panic will print a backtrace.

Signed-off-by: Anton Blanchard <[e-mail]>
Acked-by: Greg Kroah-Hartman <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

kernel/panic.c

···
 	 */
 	preempt_disable();
 
+	console_verbose();
 	bust_spinlocks(1);
 	va_start(args, fmt);
 	vsnprintf(buf, sizeof(buf), fmt, args);