misc: mic: Add include of <linux/irqreturn.h>

We currently include <linux/irqreturn.h> in <linux/pci.h>, but I'm about to
remove that from linux/pci.h, so add explicit includes where needed.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Sudeep Dutt <sudeep.dutt@intel.com>
diff --git a/drivers/misc/mic/card/mic_device.h b/drivers/misc/mic/card/mic_device.h
index 347b9b3..306f502 100644
--- a/drivers/misc/mic/card/mic_device.h
+++ b/drivers/misc/mic/card/mic_device.h
@@ -29,6 +29,7 @@
 
 #include <linux/workqueue.h>
 #include <linux/io.h>
+#include <linux/irqreturn.h>
 
 /**
  * struct mic_intr_info - Contains h/w specific interrupt sources info