dt-bindings: i2c: xiic: Fix a typo

Trivial fix. Correct a typo.

Fixes: f86ca414 ("dt-bindings: i2c: xiic: Migrate i2c-xiic documentation to YAML")
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Link: https://lore.kernel.org/r/1615215963-1042-1-git-send-email-shubhrajyoti.datta@xilinx.com


Signed-off-by: Rob Herring <robh@kernel.org>