drivers/rapidio: idt_gen2.c is implicitly relying on getting stat.h

Upon the trial removal of the implicit presence of module.h,
lots of files showed up that were getting the sub-includes
by default without calling them out. Fix them in advance.

Signed-off-by: Paul Gortmaker <[e-mail]>

drivers/rapidio/switches/idt_gen2.c

···
  * option) any later version.
  */
 
+#include <linux/stat.h>
 #include <linux/rio.h>
 #include <linux/rio_drv.h>
 #include <linux/rio_ids.h>