arm64: defconfig: Enable Sleep stats driver

Enable Sleep stats driver. The driver gives statistics for various
low power modes on Qualcomm Technologies, Inc. (QTI) SoCs.

Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/1634107104-22197-4-git-send-email-mkshah@codeaurora.org