ARM: uniphier: dts: add more clocks to Denali NAND controller node

Catch up with the new binding of the Denali IP where three clocks,
"nand", "nand_x", "ecc" are required.

For UniPhier SoCs, the "nand_x" and "ecc" are tied up because they
are both 200MHz.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>