ARM: tegra: make bounce buffer option common

All Tegra devices will need CONFIG_BOUNCE_BUFFER. Move it to
tegra-common.h to ensure it's always set.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>