ARM: uniphier: print Support Card info very late

Since commit 26b09c02 ("ARM: uniphier: move SBC and Support Card
init code to U-Boot proper"), the System Bus is initialized by
board_init().  The show_board_info() is called from board_init_f()
by default, so the revision register of the Micro Support Card may
not be accessed at this point.  Show its revision after the System
Bus is initialized.

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