x86/unwind: Prepend hex mask value with '0x' in unwind_dump()

In unwind_dump(), the stack mask value is printed in hex, but is
confusingly not prepended with '0x'.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/e7fe41be19d73c9f99f53082486473febfe08ffa.1492520933.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/unwind_frame.c

@@ -36,7 +36,7 @@ static void unwind_dump(struct unwind_state *state, unsigned long *sp)
 
 	dumped_before = true;
 
-	printk_deferred("unwind stack type:%d next_sp:%p mask:%lx graph_idx:%d\n",
+	printk_deferred("unwind stack type:%d next_sp:%p mask:0x%lx graph_idx:%d\n",
 			state->stack_info.type, state->stack_info.next_sp,
 			state->stack_mask, state->graph_idx);