regulator: Move regulator code in dev/regulator

We've removed kernel option EXT_RESOURCES almost two years ago.
While it was ok to have some code under a common 'extres' subdirectory
at first, we now have a lot of consumer of it and we made it mandatory
so no need to have it under a cryptic name.

Reviewed by: emaste, imp
Sponsored by: Beckhoff Automation GmbH & Co. KG
Differential Revision: https://reviews.freebsd.org/D43194

sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

arm/arm64 nvidia: Remove unused devclass arguments to DRIVER_MODULE.

arm/arm64 nvidia: Remove unused variables.

arm: arm64: Directly use #include <dt-binding/...>

We have it in the includes path and this will help the transition to the
new device-tree import in sys/contrib

TEGRA: Prepare Tegra subtree for inclusion into ARM generic kernel.
- use DEFINE_CLASS_0() for driver classes
- unify driver names
- cleanup driver definitions and bindings

Import basic support for Nvidia Jetson TK1 board and tegra124 SoC.
The following pheripherals are supported: UART, MMC, AHCI, EHCI, PCIe, I2C,
PMIC, GPIO, CPU temperature and clock.

Note: The PCIe driver is pure mash at this moment. It will be reworked
immediately when both D5237 and D2579 enter the current tree.