markers: fix sparse warnings in markers.c

char can be unsigned
kernel/marker.c:64:20: error: dubious one-bit signed bitfield
kernel/marker.c:65:14: error: dubious one-bit signed bitfield

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/marker.c

@@ -61,8 +61,8 @@ struct marker_entry {
 	int refcount;	/* Number of times armed. 0 if disarmed. */
 	struct rcu_head rcu;
 	void *oldptr;
-	char rcu_pending:1;
-	char ptype:1;
+	unsigned char rcu_pending:1;
+	unsigned char ptype:1;
 	char name[0];	/* Contains name'\0'format'\0' */
 };