ARM: uniphier: move PLL init code to U-Boot proper where possible

The PLL for the DRAM interface must be initialized in SPL, but the
others can be delayed until U-Boot proper.  Move them from SPL to
U-Boot proper to save the precious SPL memory footprint.

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