arm: davinci: Fix fallout from generic irq chip conversion

The code which does the chained handler setup was overwriting
chip_data.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Holger Hans Peter Freyther <holger@freyther.de>
Signed-off-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>