config: tegra124: usb: ehci: Fix "bootp" issue

Fix the timeout issue after running "bootp" command in u-boot
console.
TXFIFOTHRES bits of TXFILLTUNING register should be set to 0x10
after a controller reset and before RUN bit is set
(per technical reference manual).

BRANCH=none
BUG=chrome-os-partner:23539
TEST=install USB LAN device to USB3 port (closer to LCD panel of
Tegra124 Venice2 platform) Connect LAN cable. Run "usb reset".
Run "bootp". No EHCI timeout error.

Change-Id: I2f1a45b86388cbd814bd41a79a51bcbe3f8b3489
Signed-off-by: Jim Lin <jilin@nvidia.com>
Reviewed-on: https://chromium-review.googlesource.com/174505
Reviewed-by: Tom Warren <twarren@nvidia.com>
Reviewed-by: Jimmy Zhang <jimmzhang@nvidia.com>
Tested-by: Jimmy Zhang <jimmzhang@nvidia.com>
Reviewed-by: Andrew Bresticker <abrestic@chromium.org>
Tested-by: Andrew Bresticker <abrestic@chromium.org>
Commit-Queue: Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>