EDAC, fsl_ddr: Replace simple_strtoul() with kstrtoul()

Replace obsolete simple_strtoul() with kstrtoul().

Signed-off-by: York Sun <york.sun@nxp.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1471990593-27536-1-git-send-email-york.sun@nxp.com


Signed-off-by: Borislav Petkov <bp@suse.de>