Add ksdk gpio driver

[zephyrbot]

Reported by Maureen Helm:

Add ksdk gpio driver

(Imported from Jira ZEP-1394)

[zephyrbot]

by Mark Linkmeyer:

Hi Maureen Helm , I know this is in Code Review, but can you set the priority? Until I get the priority changes we talked about implemented, please use this: Highest = must-have, High = should-have, Med = nice-to-have. Thanks!

[zephyrbot]

by Maureen Helm:

Hi Mark Linkmeyer . Done.

[zephyrbot]

by Mark Linkmeyer:

Correcting the priority field

[zephyrbot]

Blocks GH-2942