ARM: tegra: clock: remove unused clock entry for i2c

Tegra20 clock table have the entry for clock (tegra_i2c.x, "i2c")
which is no more require as driver acquire clock with name of
"div-clk" and "fast-clk".
Remove these entries from table.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>