fbdev: omapfb: remove unused variable

Removing the default display name left a harmless warning:

fbdev/omap2/omapfb/dss/core.c: In function 'omap_dss_probe':
fbdev/omap2/omapfb/dss/core.c:196:30: error: unused variable 'pdata' [-Werror=unused-variable]

This removes the now-unused variable as well.

Fixes: 278cba7e ("drm: omapdrm: Remove unused default display name support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>