usb: usbtmc: Optimize usbtmc_write

Use new usbtmc_generic_write function to maximize bandwidth
during long data transfer.
The maximum output transfer size is limited to INT_MAX (=2GB).

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>