fsi: sbefifo: Don't fail operations when in SBE IPL state

SBE fifo operations should be allowed while the SBE is in any of the
"IPL" states. Operations should succeed in this state.

Fixes: 9f4a8a2d fsi/sbefifo: Add driver for the SBE FIFO
Reviewed-by: Joel Stanley <joel@jms.id.au>
Tested-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/1561575415-3282-1-git-send-email-eajames@linux.ibm.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>