cleanup timeout_alarm public API

:Release Notes:
Several implementation methods are removed from the global
namespace.

:Detailed Notes:
alarms/timeout_alarm.c contains a number of purely module-scope
methods which were not defined as static, thus polluting the
global namespace for the component.

:Testing Performed:
Standalone build to ensure methods were not used elsewhere.

:QA Notes:
This commit makes no change to the image.

:Issues Addressed:

Open-webOS-DCO-1.0-Signed-off-by: Nikolay Orliuk <nikolay.orliuk@lge.com>

Change-Id: Ib89026fbce88464f192b06b5bf958a8ff94c7398
Open-webOS-DCO-1.0-Signed-off-by: Keith Derrick <keith.derrick@lge.com>
Reviewed-on: https://g2g.palm.com/3858
Reviewed-by: Build Verification
Reviewed-by: Keith Derrick <keith.derrick@lge.com>
Tested-by: Keith Derrick <keith.derrick@lge.com>