Revert "ARM: uniphier: fix ROM boot mode for PH1-sLD3"

This reverts commit 82d075e7.

Commit 82d075e7 ("ARM: uniphier: fix ROM boot mode for PH1-sLD3")
was a workaround for sLD3.  Now the sLD3 SoC support has been removed.

Revert it to allow to simplify the init code.

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