ARM: rmobile: Remove SH SDHI probing from ULCB board

Drop the SH SDHI bit from the board since SD now probes from DT instead.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>