tracing: Change offset type to s32 in preempt/irq tracepoints

Discussion in the below link reported that symbols in modules can appear
to be before _stext on ARM architecture, causing wrapping with the
offsets of this tracepoint. Change the offset type to s32 to fix this.

Link: http://lore.kernel.org/r/[e-mail]
Link: http://lkml.kernel.org/r/[e-mail]

Cc: Bjorn Helgaas <[e-mail]>
Cc: David Sterba <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Mike Rapoport <[e-mail]>
Cc: "Rafael J. Wysocki" <[e-mail]>
Cc: Sakari Ailus <[e-mail]>
Cc: Antonio Borneo <[e-mail]>
Cc: [e-mail]
Fixes: d59158162e032 ("tracing: Add support for preempt and irq enable/disable events")
Signed-off-by: Joel Fernandes (Google) <[e-mail]>
Signed-off-by: Steven Rostedt (VMware) <[e-mail]>

include/trace/events/preemptirq.h

···
 	TP_ARGS(ip, parent_ip),
 
 	TP_STRUCT__entry(
-		__field(u32, caller_offs)
-		__field(u32, parent_offs)
+		__field(s32, caller_offs)
+		__field(s32, parent_offs)
 	),
 
 	TP_fast_assign(
-		__entry->caller_offs = (u32)(ip - (unsigned long)_stext);
-		__entry->parent_offs = (u32)(parent_ip - (unsigned long)_stext);
+		__entry->caller_offs = (s32)(ip - (unsigned long)_stext);
+		__entry->parent_offs = (s32)(parent_ip - (unsigned long)_stext);
 	),
 
 	TP_printk("caller=%pS parent=%pS",