i2c: tegra: clean up macros

Clean up macros by:
1) removing unused macros
2) replace constants by macro BIT()

Signed-off-by: Bitan Biswas <bbiswas@nvidia.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>