i2c: davinci: switch to use platform_get_irq

Switch Davinci I2C driver to use platform_get_irq(), because
it is not recommened to use platform_get_resource(pdev, IORESOURCE_IRQ, ..)
for requesting IRQ resources any more, as they can be not ready yet
in case of DT-boot.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>