fbdev: atafb: Modernize printing of kernel messages

Now the driver has been converted to a platform driver, the legacy
printk() calls without any log level can be replaced by proper dev_*()
calls.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Michael Schmitz <schmitzmic@gmail.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>