syscon: Move syscon code in dev/syscon

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: mhorne
Sponsored by: Beckhoff Automation GmbH & Co. KG
Differential Revision: https://reviews.freebsd.org/D43196

sys: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

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

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

arm ti: Remove unused devclass arguments to DRIVER_MODULE.

Move Ti AM335x to dev/extres/clk framework.

Re-implement clocks for these SoC by using now standard extres/clk framework.
This is necessary for future expansion of these. The new implementation
is (due to the size of the patch) only the initial (minimum) version.
It will be updated/expanded with a subsequent set of particular patches.

This patch is also not tested on OMAP4 based boards (BeagleBone),
so all possible issues should be (and will be) fixed by ASAP once
identified.

Submited by: Oskar Holmlund (oskar.holmlund@ohdata.se)
Differential Revision: https://reviews.freebsd.org/D25118

Stop including fdt_common.h from the arm code when it's unneeded.

Sponsored by: ABT Systems Ltd

Fix a random memory overwrite at boot time, simplebus_init() and
simplebus_add_device() expect a simplebus_softc structure associated with
the device.

Add the simplebus_softc as first member in am335x_pwmss_softc structure.

Sponsored by: Rubicon Communications (Netgate)

Switch TI platform support code from using FreeBSD's custom-baked DTS
files to vendor-provided ones. It should make easier to adopt platform
code to new revisions of hardware and to use DTS overlays for various
Beaglebone extensions (shields/capes).

Original dts filenames were not changed, they're now wrappers over dts
files provided by TI. So make sure you update .dtb files on your
devices as part of kernel update

GPIO addressing was changed: instead of one global /dev/gpioc0 there
are per-bank instances of /dev/gpiocX. Each bank has 32 pins so for
instance pin 121 on /dev/gpioc0 in old addressing scheme is now pin 25
on /dev/gpioc3

On Pandaboard serial console devices was changed from /dev/ttyu0 to
/dev/ttyu2 so you'll have to update /etc/ttys to get login prompt
on serial port in multiuser mode. Single user mode serial console
should work as-is

Differential Revision: https://reviews.freebsd.org/D2146
Reviewed by: rpaulo, ian, Michal Meloun, Svatopluk Kraus