video/fbdev/stifb: Delete an error message for a failed memory allocation in stifb_init_fb()

Omit an extra message for a memory allocation failure in this function.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E. J. Bottomley" <jejb@parisc-linux.org>
Cc: Rolf Eike Beer <eike-kernel@sf-tec.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>