ARM: tegra: fix RTC0 alias for Cardhu

This alias entry was evidently cut/paste from a different board, and
not correctly updated to match Cardhu. Fix this.

Fixes: 553c0a20 ("ARM: tegra: set up /aliases entries for RTCs")
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Olof Johansson <olof@lixom.net>