ARM: tegra: do v7_invalidate_l1 only when CPU is Cortex-A9

The v7_invalidate_l1 was used for the L1 cache that come out from reset
in a undefined state. This is no need for Cortex-A15. We do it for A9
only.

Signed-off-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>