defconfig: sdm845: enable SPMI temperature alarm driver

Enable CONFIG_QCOM_SPMI_TEMP_ALARM so that the
qcom-spmi-temp-alarm driver can be be used to monitor the exact
PMI8998 PMIC die temperature.  It uses iio to read the die
temperature channel from the rradc driver.

Change-Id: Ic5caf114aa977e790cd31e61651acaa1b722b5bb
Signed-off-by: David Collins <collinsd@codeaurora.org>