Revert "wext: Fix 32 bit iwpriv compatibility issue with 64 bit Kernel"

This reverts commit 3d5fdff4.

Ben Hutchings pointed out that the commit isn't safe since it assumes
that the structure used by the driver is iw_point, when in fact there's
no way to know about that.

Fortunately, the only driver in the tree that ever runs this code path
is the wilc1000 staging driver, so it doesn't really matter.

Clearly I should have investigated this better before applying, sorry.

Reported-by: Ben Hutchings <ben@decadent.org.uk>
Cc: stable@vger.kernel.org [though I guess it doesn't matter much]
Fixes: 3d5fdff4 ("wext: Fix 32 bit iwpriv compatibility issue with 64 bit Kernel")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>