i2c: tegra: disable clock before returning error

Disable clock before returning error in tegra_i2c_init() as its leaves
i2c clock ON in case of error and never turns off again as it will have
unbalanced clock enable/disable

Signed-off-by: Shardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>