i2c: tegra: remove multi-master support

Multi-master support is defeatured on Tegra210 and Tegra186 due to
known bugs.

This patch removes multi-master support for Tegra210 and Tegra186
I2C HW feature.

Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>