dt-bindings: i2c: qcom-cci: Document sa8775p compatible

Add the sa8775p CCI device string compatible.

Acked-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Wenmeng Liu <quic_wenmliu@qualcomm.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>