usb: usbtmc: Add support for 32 bit compat applications

32 bit applications can only call ioctl functions on 64 bit systems
when the field .compat_ioctl is defined for file operations.

Tested-by: Dave Penkler <dpenkler@gmail.com>
Signed-off-by: Guido Kiener <guido.kiener@rohde-schwarz.com>
Reviewed-by: Steve Bayless <steve_bayless@keysight.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>