ARM: dts: qcom: apq8064: add missing clocks to the timer node

ARM: dts: qcom: apq8064: add missing clocks to the timer node

In order to fix DT schema warning and describe hardware properly, add
missing sleep clock to the timer node.

Fixes: f335b8af4fd5 ("ARM: dts: qcom: Add initial APQ8064 SoC and IFC6410 board device trees")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250318-fix-nexus-4-v2-6-bcedd1406790@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>