Add K64F clock configurations

[zephyrbot]

Reported by Maureen Helm:

Currently the K64F SoC init assumes the external reference clock frequency is that of the Freedom board. Other K64F boards (Hexiwear, for example) may have a different external reference clock or oscillator, and therefore require a different clock configuration.

(Imported from Jira ZEP-715)

[zephyrbot]

by Mark Linkmeyer:

Hi Maureen Helm , who's the right person to verify this has been fixed so it can be moved to the Verified state then to the Closed state? Thx.

[zephyrbot]

by Mark Linkmeyer:

Hi Maureen Helm , sorry to bug you, but please see my question above.

[zephyrbot]

by Maureen Helm:

Hi Mark Linkmeyer . Did you see my note today on GH-2234? Same comment applies here too.

[zephyrbot]

by Mark Linkmeyer:

Thanks Maureen Helm . I hadn't yet gotten to GH-2234. It's further down on my list that I'm currently going through. :-) I see it now.

[zephyrbot]

by Mark Linkmeyer:

Maureen's reply (from GH-2234): "Sorry for the delay, I've been traveling for a few weeks. Since I reported and implemented this story, does it make sense for me to verify it too? Or do we need another person to verify? From my perspective, it is fixed."

[zephyrbot]

by Mark Linkmeyer:

I think it is totally fine since you're the reporter. My thinking is this: Since you're the reporter you know best what the bug is and how to reproduce it. As such, you're the absolute best person to know if it was actually fixed, regardless of whether you were the implementer of the fix. Since you're saying it's fixed, I'll move it to Verified for you. Thx.