i2c: davinci: remove useless mach/hardware include

This driver no longer uses definitions from mach/hardware.h.
On the other hand, including this header breaks this driver
on non-davinci platforms which don't have such a header.

Acked-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>