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/

proto: Remove unused devclass arguments to DRIVER_MODULE.

Check the hw.proto.attach environment variable for devices that
proto(4) should attach to instead of the normal driver.

Document the variable.

Change the probe to what was intended: attach to devices with
a type 0 header and not to function 0 devices.

We need to handle 64-bit BARs ourselves to avoid that the
PCI infrastructure instantiates a non-existent resource.
This has BARs suddenly show up with pciconf(8) under
VMware as well. Now that we read the BAR ourselves, ask
for the correct resource type.

DMA support part 1: DMA tag create & destroy

Create a special resource (= device special file) for management
of tags and maps, as well as for mapping memory into the address
space. DMA resources are managed using the PROTO_IOC_BUSDMA ioctl.
Part 1 implements tag creation, derivation and destruction.

Add proto(4): A driver for prototyping and diagnostics.
It exposes I/O resources to user space, so that programs can peek
and poke at the hardware. It does not itself have knowledge about
the hardware device it attaches to.

Sponsored by: Juniper Networks, Inc.