irqchip/davinci-cp-intc: Remove public header

There are no more users of irq-davinci-cp-intc.h (da830.c doesn't use
any of its symbols). Remove the header and make the driver stop using the
config structure.

[ tglx: Mop up coding style ]

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250304131815.86549-1-brgl@bgdev.pl