i2c: tegra: don't open code of_device_get_match_data()

This change will also make Coverity happy by avoiding a theoretical NULL
pointer dereference; yet another reason is to use the above helper function
to tighten the code and make it more readable.

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>
Tested-by: Laxman Dewangan <ldewangan@nvidia.com>