wandboard: Remove cpu type check prior to setup_sata()

Inside setup_sata() there is a cpu type check, so there is no need to
do this check in the board file.

This also brings the benefit to allowing setup_sata() to be called for the
mx6qp wandboard variant.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>