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: clean up empty lines in .c and .h files

Lock busdma operations and serialize detach against open/close

Use sx to allow M_WAITOK allocations (suggested by markj).

admbugs: 782
Reviewed by: markj

Check the sync operation.

o make sure the boundary is a power of 2, when not zero.
o don't convert 0 to ~0 just so that we can use MIN. ~0 is not a
valid boundary. Introduce BNDRY_MIN that deals with 0 values
that mean no boundary.

Implement unload and sync operations.

Add create, destroy and load of memory descriptors.

Load the allocated memory and return both the physical
address and the bus address to the application.

Implement mmap(2) for the busdma resource.

Add DMA memory allocation and freeing.
Slightly rework the tag handling.

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.