usb_updater2: increase send timeout to 2s
usb_updater2: increase send timeout to 2s

To 'successfully' flash sweetberry the 1s timeout is not sufficient.
Increase to 2s.

BRANCH=None
BUG=b:120449224
TEST=manual test
sudo servo_updater --board sweetberry
...
offset: writable at 0x40000
sending 0xb580 bytes to 0x40000
-------
update complete
image updated
...

Change-Id: I38bf8c852caf97069fcf67f4b77f9c0a30008235
Signed-off-by: Ruben Rodriguez Buchillon <12b0357cd989b603267f0b7cb81c747471f94bd1@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1369507
Commit-Ready: ChromeOS CL Exonerator Bot <fa429e5907f00867f797423aea74327bb02c91b6@appspot.gserviceaccount.com>
Reviewed-by: Nicolas Boichat <f3daba1cdc403799935674d3cd4b0e5bd1804232@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec