mtd: rawnand: omap_gpmc: Enable build for K2/K3 platforms

The GPMC module is present on some K2 and K3 SoCs.
Enable building GPMC NAND driver for K2/K3 platforms.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Reviewed-By: Michael Trimarchi <michael@amarulasolutions.com>
Link: https://lore.kernel.org/all/20221011115012.6181-3-rogerq@kernel.org


Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>