mmc: tmio: don't overwrite caps2

02cb3221 ("mmc: tmio: support caps2 flags") added caps2 support on
tmio, but it overwrites mmc_of_parse() settings.  This patch fixes it.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: Laurent <laurent.pinchart@ideasonboard.com>
Signed-off-by: Chris Ball <cjb@laptop.org>