arm64: defconfig: Enable the PM8xxx RTC driver

Enable the driver for the real time clock found in the PMICs on various
Qualcomm platforms.

Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
Link: https://lore.kernel.org/r/20200616090324.6976-1-georgi.djakov@linaro.org


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