wl1251: use wl12xx_platform_data to pass data

Make use the newly added method to pass platform data for wl1251 too.
This allows to eliminate some redundant code.

Cc: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Acked-by: Kalle Valo <kvalo@adurom.com>
Acked-by: Luciano Coelho <luciano.coelho@nokia.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>