dt-bindings: qcom: Document bindings for new msm8916-samsung-e2015 devices

Document the new samsung,e5/e7/grandmax device tree bindings used in their
device trees.

Signed-off-by: Lin, Meng-Bo <linmengbo0689@protonmail.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220724095346.14022-1-linmengbo0689@protonmail.com