staging: ft1000: return values corrected in scram_start_dwnld

The ft1000 usb driver ignores expected Linux error codes, and uses two
values defined in ft1000_usb.h: STATUS_SUCCESS 0, and STATUS_FAILURE
0x1001; and sometimes -1. This patch changes the return values of the
function scram_start_dwnld to match the status of the handshake returned
by its helper functions, get_handshake and get_handshake_usb. If the
handshake fails, -ENETRESET is returned instead of the inappropriate
STATUS_FAILURE. Also, a new test has been added to differentiate failure
due to timeout from failure due to net reset (the default). -ETIMEDOUT
is returned in this case. Finally, 0 is returned on success instead of
STATUS_SUCCESS.

Signed-off-by: Kelley Nielsen <kelleynnn@gmail.com>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>