dt: tegra: remove non-existent clock IDs

The Tegra124 clock DT binding currently provides 3 clocks that don't
actually exist; 2 for NAND and one for UART5/UARTE. Delete these. While
this is technically an incompatible DT ABI change, nothing could have
used these clock IDs for anything practical, since the HW doesn't exist.

Cc: <stable@vger.kernel.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>