tpm: tpm_i2c_infinion: Don't modify i2c_client->driver

The I2C client driver is not supposed to modify the client's driver pointer,
this is handled by the I2C core.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>