ARM: OMAP2+: Make sure pandora_wl1251_init_card() applies to SDIO only

In preparation for having init_card() called for all card types (not
just SDIO), change pandora_wl1251_init_card() so it checks whether the
card type is SDIO.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>