i2c: davinci: use correct format identifier for size_t

Fixes this warning (found by build testing with 64bit):

format ‘%i’ expects argument of type ‘int’, but argument 3 has type
‘size_t {aka long unsigned int}’ [-Wformat=]

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