ARM: davinci: cp-intc: remove cp_intc.h

There's no need to have a local header for cp-intc. Move the only
declaration for a public function to common.h. Move all register
offsets into the driver source file and drop all unused defines.
Make cp_intc_of_init() static.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: David Lechner <david@lechnology.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>