staging: kpc2000: add initial set of Daktronics drivers

These drivers have been outside of the kernel tree since the 2.x days,
and it's time to bring them into the tree so they can get properly
cleaned up.

This first dump of drivers is based on a tarball Matt gave to me, minus
an odd "dma" driver that I could not get to build at all.  I renamed a
few files, added the proper SPDX lines to it, added Kconfig entries and
tied it into the kernel build.  I also fixed up a number of initial
obvious kernel build warnings, but left the odd bitfield warning that
gcc is spitting out, as I'm not quite sure what to do about that.

There's loads of low-hanging coding style cleanups in here for people to
start attacking, as well as the more obvious logic and api cleanups as
well.

Cc: Matt Sickler <Matt.Sickler@daktronics.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>