i2c: tegra: Fix regression by implementing a dummy probe_chip() callback

i2c: tegra: Fix regression by implementing a dummy probe_chip() callback

Commit 5bf80e4363bf ("dm: i2c: Make i2c_get_chip_for_busnum() fail if the
chip is not detected") introduced a regression for the NVIDIA Jetson TX2.

For some reason the xfer callback of the tegra i2c driver doesn't support
probing the I2C devices with a 0-length message.
Fixing the regression by providing a dummy implementation of probe_chip()
that does nothing.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Tested-by: Stephen Warren <swarren@nvidia.com>