arm64: defconfig: Enable Qualcomm LMH driver

With the introduction of LMH in '36c65812 ("arm64: dts: qcom:
sdm845: Add support for LMh node")' the CPUfreq gained a reference for
the two interrupts from the LMh. This means that if the LMh driver isn't
enabled CPUfreq will not probe and there's no frequency scaling.

Enable LMh to make CPUfreq functional again on SDM845.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>