arm/tegra: rename tegra20 pinmux files

Rename pinmux-t2.h and pinmux-t2-tables.c to the new tegra naming. This file
will be reworked somewhat in the next patch to support multiple tegra SoC
types.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Acked-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Colin Cross <ccross@android.com>
Signed-off-by: Olof Johansson <olof@lixom.net>