i2c: nvidia-gpu: Use PTR_ERR_OR_ZERO() to simplify code

PTR_ERR_OR_ZERO contains if(IS_ERR(...)) + PTR_ERR.

Generated by: scripts/coccinelle/api/ptr_ret.cocci

Signed-off-by: Aishwarya Ramakrishnan <aishwaryarj100@gmail.com>
Reviewed-by: Ajay Gupta <ajayg@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>