staging: vt6656: simplify tests of successful urb status

Use if (status) in tests for successful urb status.

This replaces (status != 0) and (status == STATUS_SUCCESS).
(STATUS_SUCCESS is defined for NDIS status in this driver, but
was being misused)

Signed-off-by: Alison Schofield <amsfield22@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>