[RFC] VGDrvCommonIoCtl: Add f32bit flag argument

[Hans de Goede <hdegoede@redhat.com>]

Note to linux-kernel readers: This Cc-ed to linux-kernel because it is
relevant for the "[RFC 0/2] Add Virtual Box vboxguest and vboxsf guest
drivers to the mainline kernel" thread.

Hi Michael, Knut,

My first submission of the vboxguest driver for inclusion into
the Linux kernel has lead to some questions about the use of the
VBOXGUEST_IOCTL_FLAG to differentiate between 32 and 64 bit
ioctls. Under Linux this is not necessary, as the driver already
knows if it is serving a 32 bit compat or a regular ioctl.

So I've come up with this patch to make VBOXGUEST_IOCTL_FLAG
always 0 under Linux. I was hoping the f32bit flag could be
used under more platforms so that it would actually be a cleanup,
but it seems that Linux is the only platform with a compat_ioctl
callback in its file-operations struct.

Please let me know if you would be willing to merge this patch
into upstream VirtualBox.

Regards,

Hans