defconfig: Enable wdt ping to cores in low power mode for sdm670 and sdm845

The watchdog IPI optimization is to not ping cores in low power modes at
pet time, which is enabled by default.

Disable this optimization in debug builds of sdm670 and sdm845 targets.

Change-Id: Ieba65c9a30b5f7409971929d60dfd8b3465d6529
Signed-off-by: Lingutla Chandrasekhar <clingutla@codeaurora.org>