drivers: i2c_rtio: Use MCUX variations when using instance number

Update the driver to account for variations in the SDK driver
when it uses the instance number instead of the base address.

Applying 49bdcd2ef2fd5c91ab36f08d29e5183df5437843 on RTIO-version.

Co-authored-by: Mahesh Mahadevan <mahesh.mahadevan@nxp.com>
Signed-off-by: Luis Ubieda <luisf@croxel.com>
(cherry picked from commit 0f0bb7e6)