ARM: uniphier: refactor DDR PHY parameter dump command

Do not hard-code the number of DX blocks because it is a different
value for LD11 SoC.

Move the macro NR_DATX8_PER_DDRPHY to ddrphy-training.c since it
is the last user.

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