Problem

• System.ticks() returns 0 currently on P2 and TrackerM platforms.
• System.ticksDelay() also doesn't work.
• System.ticksPerMicrosecond() is wrong.

Solution

• Ideally we'd have a hardware timer to use to hook up to System.ticks() like the rest of Gen 3 devices do, but the only one with a fast enough clock speed is currently being used for the RTC implementation and only has a 16-bit register anyway.
• Instead of just disabling System.ticks() we have implemented a stop gap of tying it to the micros() counter when the system does not support a system tick hardware counter.
• System.ticks() and micros() are essentially the same value on rtl872x based platforms now.
• System.ticksDelay() works like delayMicroseconds()
• System.ticksPerMicrosecond() returns 1

Steps to Test

• Run TEST=wiring/no_fixture SYSTEM_08/SYSTEM_09

Completeness

• User is totes amazing for contributing!
• Contributor has signed CLA (Info here)
• Problem and Solution clearly stated
• Run unit/integration/application tests on device
• Added documentation
• Added to CHANGELOG.md after merging (add links to docs and issues)