defconfig: sdm855: Enable HARDIDLETIMER

For fast dormancy feature, network idle timer support is required
where in timer expires even in power colapse and which triggers a
sysfs notification. If a matching packet is received then timer is
reset. This support is required in the kernel so enabling the config

Change-Id: I959d035011304fe2dd3465deb337b2087634cca2
Signed-off-by: Bhavya Sokke Mallikarjunappa <bsokke@codeaurora.org>
Signed-off-by: Tejaswi Tanikella <tejaswit@codeaurora.org>