i2c: tegra: Fix missing blank lines after declarations

Checkpatch warns about missing blank lines after declarations in the
Tegra I2C driver and so fix these.

Note that the initialisation of 'val' to zero in tegra_dvc_init() is
unnecessary and so remove this.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>