dt-bindings: arm: qcom: add oneplus3(t) devices

Add compatible strings for the OnePlus 3 and 3T phones which utilise the
Qualcomm MSM8996 SoC.

Signed-off-by: Harry Austen <hpausten@protonmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221023204505.115141-4-hpausten@protonmail.com