If we fall back to using LSI on the Croc or Crocodile chip we need to
clear the interrupt so we don't hang the system.

Cc: <stable@vger.kernel.org>
Tested-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NBrian King <brking@linux.vnet.ibm.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>