RAS/AMD/FMPM: Fix off by one when unwinding on error

Decrement the index variable i before the first iteration when freeing
the remaining elements on error. Depending on where this fails it could
free something from one element beyond the end of the fru_records[]
array.

  [ bp: Massage commit message. ]

Fixes: 6f15e617

 ("RAS: Introduce a FRU memory poison manager")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/6fdec71a-846b-4cd0-af69-e5f6cd12f4f6@moroto.mountain