dt-bindings: arm: msm: Don't mark LLCC interrupt as required

Newer SoCs like SM6350 or SM8250 don't provide an interrupt for LLCC.

Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
Acked-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20211213082614.22651-9-luca.weiss@fairphone.com