ksdk: Import Kinetis SDK drivers

The Kinetis SDK provides device header files and peripheral drivers for Kinetis
SOCs. Importing a subset of the SDK to support the K64F peripherals. This will
make it possible to implement a shim layer to adapt the drivers to Zephyr APIs.

Origin: NXP KSDK 2.0
URL: kex.nxp.com
Maintained-by: External

Change-Id: Ie14b42f75dab9126eb1ca4653538c5707b830cb5
Signed-off-by: Maureen Helm <maureen.helm@nxp.com>