DMA-API: crypto: fix ixp4xx crypto platform device support

Don't statically allocate struct device's in modules, and shut the
warning up with an empty release() function.  There's a reason that
warning is there and that's not for people to hide in this way.  It's
there to persuade people to use the correct APIs to allocate platform
devices.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>