MIPS: Alchemy: Fix typo in MAC0 registration

Harmless typo which prints an error message although MAC0 was registered
successfully.

Signed-off-by: Manuel Lauss <manuel.lauss@googlemail.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2672/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>