[ARM] always allow dump_stack() to produce a backtrace

Don't make this dependent on CONFIG_DEBUG_KERNEL - if we hit a WARN_ON
we need the stack trace to work out how we got to that point.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/traps.c

@@ -181,9 +181,7 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 
 void dump_stack(void)
 {
-#ifdef CONFIG_DEBUG_ERRORS
 	__backtrace();
-#endif
 }
 
 EXPORT_SYMBOL(dump_stack);