hw/display/sm501: Implement more 2D raster operations

hw/display/sm501: Implement more 2D raster operations

Add simple implementation for two raster operations that are used by
AmigaOS which fixes graphics problems in some programs using these.

Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Reported-by: Rene Engel <ReneEngel80@emailn.de>
Tested-by: Rene Engel <ReneEngel80@emailn.de>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <17ef3c59dc7868f75034e9ebe21e2999c8f718d4.1677445307.git.balaton@eik.bme.hu>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>