dt-bindings: Update Sibi Sankar's email address

Update email address to the quicinc.com domain.

Signed-off-by: Sibi Sankar <quic_sibis@quicinc.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/1654130923-18722-1-git-send-email-quic_sibis@quicinc.com