powerpc/pseries/ras: Delete a redundant condition branch

The statement of the last "if (xxx)" branch is the same as the "else"
branch. Delete it to simplify code.

No functional change.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210510131924.3907-1-thunder.leizhen@huawei.com