EDAC/sb_edac: Remove redundant update of tad_base

The variable tad_base is being set to a value that is never read and is
being over-written on the next iteration of a for-loop. This assignment
is therefore redundant and can be removed.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Tony Luck <tony.luck@intel.com>
Cc: James Morse <james.morse@arm.com>
Cc: kernel-janitors@vger.kernel.org
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Link: https://lkml.kernel.org/r/20190508224201.27120-1-colin.king@canonical.com