PM / QoS: Drop redundant declaration of pm_qos_get_value()

The extra forward declaration of pm_qos_get_value() is redundant, so
drop it.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

kernel/power/qos.c

@@ -184,7 +184,6 @@ static inline void pm_qos_set_value(struct pm_qos_constraints *c, s32 value)
 	c->target_value = value;
 }
 
-static inline int pm_qos_get_value(struct pm_qos_constraints *c);
 static int pm_qos_dbg_show_requests(struct seq_file *s, void *unused)
 {
 	struct pm_qos_object *qos = (struct pm_qos_object *)s->private;