docbook: fix fatal errors in device-drivers docbook and add DMA Management section

docbook: fix fatal errors in device-drivers docbook and add DMA Management section

Fix 2 fatal errors in the device-drivers docbook.
Also add some missing files from drivers/base/; since several
of these are DMA-related, add a section for DMA Management.

docproc: drivers/base/sys.c: No such file or directory
docproc: drivers/tty/serial/8250.c: No such file or directory

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>