WANDBOARD.common kernel config will be deleted

[Ian Lepore]

This is just a heads-up for anyone who has a custom kernel config that's
doing "include WANDBOARD.common" ... that config is going to be deleted
soon.  Please change your include to "IMX6" instead (they're equivelent
except that SMP is enabled in IMX6).  

I've adjusted the three WANDBOARD-<boardtype> configs to include IMX6.
Those board-type configs are eventually going to be deleted too, but
we're missing a couple bits of build infrastructure needed to specify
which .dts file(s) you want compiled if they're not compiled into the
kernel.

-- Ian