virt: acrn: Use vfs_poll() instead of f_op->poll()

Use a more advanced function vfs_poll() in acrn_irqfd_assign().
At the same time, modify the definition of events.
Signed-off-by: NYejune Deng <yejune.deng@gmail.com>
Signed-off-by: NShuo Liu <shuo.a.liu@intel.com>
Link: https://lore.kernel.org/r/20210221133306.33530-1-shuo.a.liu@intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/virt/acrn/irqfd.c

@@ -112,7 +112,7 @@ static int acrn_irqfd_assign(struct acrn_vm *vm, struct acrn_irqfd *args)
 {
 	struct eventfd_ctx *eventfd = NULL;
 	struct hsm_irqfd *irqfd, *tmp;
-	unsigned int events;
+	__poll_t events;
 	struct fd f;
 	int ret = 0;
 
@@ -158,7 +158,7 @@ static int acrn_irqfd_assign(struct acrn_vm *vm, struct acrn_irqfd *args)
 	mutex_unlock(&vm->irqfds_lock);
 
 	/* Check the pending event in this stage */
-	events = f.file->f_op->poll(f.file, &irqfd->pt);
+	events = vfs_poll(f.file, &irqfd->pt);
 
 	if (events & POLLIN)
 		acrn_irqfd_inject(irqfd);