staging: ti dspbridge: add driver documentation

Add a README with a general overview of TI's DSP Bridge driver,
a short explanations of how error codes are currently used,
and a CONTRIBUTORS file with all past & present contributors.

For additional information about TI's DSP Bridge,
check out http://omapzoom.org/gf/project/omapbridge/docman/?subdir=3



Note: if by any chance we forgot to mention any contributor,
please let us know and we will fix that.

Signed-off-by: Omar Ramirez Luna <omar.ramirez@ti.com>
Signed-off-by: Kanigeri, Hari <h-kanigeri2@ti.com>
Signed-off-by: Ameya Palande <ameya.palande@nokia.com>
Signed-off-by: Guzman Lugo, Fernando <fernando.lugo@ti.com>
Signed-off-by: Hebbar, Shivananda <x0hebbar@ti.com>
Signed-off-by: Ramos Falcon, Ernesto <ernesto@ti.com>
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Anna, Suman <s-anna@ti.com>
Signed-off-by: Gupta, Ramesh <grgupta@ti.com>
Signed-off-by: Gomez Castellanos, Ivan <ivan.gomez@ti.com>
Signed-off-by: Andy Shevchenko <ext-andriy.shevchenko@nokia.com>
Signed-off-by: Armando Uribe De Leon <x0095078@ti.com>
Signed-off-by: Deepak Chitriki <deepak.chitriki@ti.com>
Signed-off-by: Menon, Nishanth <nm@ti.com>
Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com>
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>