m25p80.c: Use QOM classes for part differentiation

m25p80.c: Use QOM classes for part differentiation

Currently, M25P80 uses an object property to differentiate between flash parts.
Changed this over to use QOM sub-classes - the actual names of the different parts
are used to create a set of dynamic classes which passes the part info as class
data. The object no longer needs to search the known_devices table for itself,
instead it just gets its info from its own class.

Kept the intermediate class definition private to m25p80.c for the moment, as
the expectation is parts will only be added as new entries in the table. We can
factor out the TYPE_M25P80 abstraction into a header on a demand basis.

Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Message-id: e24e156d-ff96-4901-997a-e31178b08bee@VA3EHSMHS021.ehs.local
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>