acpi_gpiobus: Reuse the existing IVAR index for an ACPI handle

ACPI_IVAR_HANDLE is a global index shared across multiple busses,
there is no need for a unique constant here.

Reviewed by:	vexeduxr, imp
Differential Revision:	https://reviews.freebsd.org/D54155

sys/dev/gpio/acpi_gpiobus.c

@@ -401,7 +401,7 @@ acpi_gpiobus_read_ivar(device_t dev, device_t child, int which,
 	struct acpi_gpiobus_ivar *devi = device_get_ivars(child);
 
 	switch (which) {
-	case ACPI_GPIOBUS_IVAR_HANDLE:
+	case ACPI_IVAR_HANDLE:
 		*result = (uintptr_t)devi->handle;
 		break;
 	default:

sys/dev/gpio/acpi_gpiobusvar.h

@@ -28,21 +28,8 @@
 #ifndef	__ACPI_GPIOBUS_H__
 #define	__ACPI_GPIOBUS_H__
 
-#include <sys/bus.h>
-
 #include <contrib/dev/acpica/include/acpi.h>
 
-enum acpi_gpiobus_ivars {
-	ACPI_GPIOBUS_IVAR_HANDLE	= 10600
-};
-
-#define ACPI_GPIOBUS_ACCESSOR(var, ivar, type)			\
-	__BUS_ACCESSOR(acpi_gpiobus, var, ACPI_GPIOBUS, ivar, type)
-
-ACPI_GPIOBUS_ACCESSOR(handle,	HANDLE,		ACPI_HANDLE)
-
-#undef ACPI_GPIOBUS_ACCESSOR
-
 uint32_t acpi_gpiobus_convflags(ACPI_RESOURCE_GPIO *);
 
 #endif	/* __ACPI_GPIOBUS_H__ */

sys/dev/gpio/gpioaei.c

@@ -208,7 +208,7 @@ gpio_aei_attach(device_t dev)
 	/* This is us. */
 	device_set_desc(dev, "ACPI Event Information Device");
 
-	handle = acpi_gpiobus_get_handle(dev);
+	handle = acpi_get_handle(dev);
 	status = AcpiGetParent(handle, &sc->dev_handle);
 	if (ACPI_FAILURE(status)) {
 		device_printf(dev, "Cannot get parent of %s\n",