virt: vbox: Use fallthrough;

Convert the various uses of fallthrough comments to fallthrough;

Done via script
Link: https://lore.kernel.org/lkml/b56602fcf79f849e733e7b521bb0e17895d390fa.1582230379.git.joe@perches.com/

And by hand:

drivers/virt/vboxguest/vboxguest_core.c has a fallthrough comment outside
of an #ifdef block that causes gcc to emit a warning if converted in-place.

So move the new fallthrough; inside the containing #ifdef/#endif too.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/68773b4cd82288b78ca6fcde8c43e249a025378a.1584040050.git.joe@perches.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/virt/vboxguest/vboxguest_core.c

@@ -1553,8 +1553,8 @@ int vbg_core_ioctl(struct vbg_session *session, unsigned int req, void *data)
 #ifdef CONFIG_COMPAT
 	case VBG_IOCTL_HGCM_CALL_32(0):
 		f32bit = true;
+		fallthrough;
 #endif
-		/* Fall through */
 	case VBG_IOCTL_HGCM_CALL(0):
 		return vbg_ioctl_hgcm_call(gdev, session, f32bit, data);
 	case VBG_IOCTL_LOG(0):

drivers/virt/vboxguest/vboxguest_utils.c

@@ -311,7 +311,7 @@ static u32 hgcm_call_linear_addr_type_to_pagelist_flags(
 	switch (type) {
 	default:
 		WARN_ON(1);
-		/* Fall through */
+		fallthrough;
 	case VMMDEV_HGCM_PARM_TYPE_LINADDR:
 	case VMMDEV_HGCM_PARM_TYPE_LINADDR_KERNEL:
 		return VMMDEV_HGCM_F_PARM_DIRECTION_BOTH;