amd64_edac: Fix potential memleak

We check the pointers together but at least one of them could be invalid
due to failed allocation. Since we cannot continue if either of the two
allocations has failed, exit early by freeing them both.

Cc: <stable@kernel.org> # 38.x
Reported-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>