Remove unnecessary headers. Sort out the headers. Add a missing header on

ofw_gpiobus.c (it was working because of sys/libkern.h).

sys/dev/gpio/gpiobus.c

@@ -28,21 +28,16 @@
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
-#include <sys/systm.h>
+#include <sys/bus.h>
+#include <sys/gpio.h>
+#include <sys/kernel.h>
 #include <sys/malloc.h>
 #include <sys/module.h>
-#include <sys/kernel.h>
-#include <sys/queue.h>
-#include <sys/sysctl.h>
+#include <sys/systm.h>
 #include <sys/types.h>
 
-#include <sys/bus.h>
-#include <machine/bus.h>
-#include <sys/rman.h>
-#include <machine/resource.h>
-
-#include <sys/gpio.h>
 #include <dev/gpio/gpiobusvar.h>
+
 #include "gpio_if.h"
 #include "gpiobus_if.h"
 

sys/dev/gpio/ofw_gpiobus.c

@@ -33,17 +33,13 @@ __FBSDID("$FreeBSD$");
 #include <sys/bus.h>
 #include <sys/gpio.h>
 #include <sys/kernel.h>
-#include <sys/libkern.h>
-#include <sys/lock.h>
 #include <sys/module.h>
-#include <sys/mutex.h>
+#include <sys/systm.h>
 
 #include <dev/gpio/gpiobusvar.h>
 #include <dev/ofw/ofw_bus.h>
 #include <dev/ofw/openfirm.h>
 
-#include <machine/resource.h>
-
 #include "gpio_if.h"
 #include "gpiobus_if.h"