virt: vbox: linux: fix all kernel-doc warnings

Use kernel-doc format for functions that are almost complete in their
kernel-doc comments.
For other functions, just change the comment to a common C comment.
This prevents 7 kernel-doc warnings.

Signed-off-by: Randy Dunlap <[e-mail]>
Cc: Hans de Goede <[e-mail]>
Cc: Arnd Bergmann <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/virt/vboxguest/vboxguest_linux.c

···
 }
 
 /**
- * Close device.
- * Return: 0 on success, negated errno on failure.
+ * vbg_misc_device_close - Close device.
  * @inode:		Pointer to inode info structure.
  * @filp:		Associated file pointer.
+ *
+ * Return: %0 on success, negated errno on failure.
  */
 static int vbg_misc_device_close(struct inode *inode, struct file *filp)
 {
···
 }
 
 /**
- * Device I/O Control entry point.
- * Return: 0 on success, negated errno on failure.
+ * vbg_misc_device_ioctl - Device I/O Control entry point.
  * @filp:		Associated file pointer.
  * @req:		The request specified to ioctl().
  * @arg:		The argument specified to ioctl().
+ *
+ * Return: %0 on success, negated errno on failure.
  */
 static long vbg_misc_device_ioctl(struct file *filp, unsigned int req,
 				  unsigned long arg)
···
 	return ret;
 }
 
-/** The file_operations structures. */
+/* The file_operations structures. */
 static const struct file_operations vbg_misc_device_fops = {
 	.owner			= THIS_MODULE,
 	.open			= vbg_misc_device_open,
···
 #endif
 };
 
-/**
+/*
  * Called when the input device is first opened.
  *
  * Sets up absolute mouse reporting.
···
 	return vbg_core_set_mouse_status(gdev, feat);
 }
 
-/**
+/*
  * Called if all open handles to the input device are closed.
  *
  * Disables absolute reporting.
···
 	vbg_core_set_mouse_status(gdev, 0);
 }
 
-/**
+/*
  * Creates the kernel input device.
  *
  * Return: 0 on success, negated errno on failure.
···
 };
 ATTRIBUTE_GROUPS(vbg_pci);
 
-/**
+/*
  * Does the PCI detection and init of the device.
  *
  * Return: 0 on success, negated errno on failure.
···
 }
 EXPORT_SYMBOL(vbg_put_gdev);
 
-/**
+/*
  * Callback for mouse events.
  *
  * This is called at the end of the ISR, after leaving the event spinlock, if