OMAP2430: hwmod data: Use common dev_attr for i2c1 and i2c2

Since i2c1 and i2c2 are using the same data, remove the two previous
instances and use a common i2c_dev_attr one.

Moreover, that will fix the following warning:
arch/arm/mach-omap2/omap_hwmod_2430_data.c:485:
warning: 'i2c_dev_attr' defined but not used

Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Acked-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Charulatha V <charu@ti.com>