EDAC, mv64x60: Sanity check edac_op_state before registering

edac_op_state is a module parameter which affects the behaviour of
the driver probe which can potentially be invoked as soon as the
platform driver registration happens. Because of this we need to
ensure that we sanity check the module parameter before calling
platform_register_drivers().

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170607215530.8604-1-chris.packham@alliedtelesis.co.nz


Signed-off-by: Borislav Petkov <bp@suse.de>