i2c: tegra-bpmp: convert to use new atomic callbacks

The driver did handle this internally, convert it to use the new
callbacks.

Reviewed-by: Timo Alho <talho@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>