ipr: Clear interrupt on croc/crocodile when running with LSI

[ Upstream commit 54e430bbd490e18ab116afa4cd90dcc45787b3df ]

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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>