xhci-tegra fix warnings on unused function

xhci-tegra fix warnings on unused function

remove unused function warning for save_ctle_context()
the function IS used for T12x but not T11x

/nvidia/DEV_KERNEL/kernel/drivers/usb/host/xhci-tegra.c:1768:13:
warning: 'save_ctle_context' defined but not used [-Wunused-function]

Change-Id: I22aa17fcb4afca9db1356f3017b86d09c28c1814
Signed-off-by: Philip Rakity <prakity@nvidia.com>
Reviewed-on: http://git-master/r/272034
Reviewed-by: Laxman Dewangan <ldewangan@nvidia.com>
Tested-by: Laxman Dewangan <ldewangan@nvidia.com>