arm: tegra: jetson: enable Tegra GPIO PI1 for input (recovery button)

Signed-off-by: Michael Scott <michael.scott@linaro.org>
arm: tegra: check if recovery mode is already set before doing more checks

Signed-off-by: Michael Scott <michael.scott@linaro.org>
arm: tegra: jetson: add small delay to check FORCE_RECOVERY button press

By pressing the FORCE_RECOVERY button on Jetson within the first 2 seconds
of power on, it turns on "recovery" mode.  No more need for a serial cable
or working Android OS to trigger recovery.

Signed-off-by: Michael Scott <michael.scott@linaro.org>