gpio-keys-polled improvements v2

Hello folks, here's v2 of my gpio-keys-polled queue. changes v2: * removed the change in mod_devicetable.h (MODULE_DEVICE_TABLE_OF macro) * reworked the patch for building w/o oftree, so it works w/o the MODULE_DEVICE_TABLE_OF macro have fun, --mtx

gpio-keys-polled improvements

Hello folks, here're some improvements for the gpio-keys-polled driver. The first patch isn't in the driver itself, but adds a little module helper for conditionally declaring oftree module table if oftree is enabled (only needed for the last patch) have fun. --mtx