scsi: ipr: Remove obsolete check for old CPUs

The IPR driver has a routine to check whether it's running on certain CPU
versions and if so whether the adapter is supported on that CPU.

But none of the CPUs it checks for are supported by Linux anymore.

The most recent CPU it checks for is Power4+ which was removed in commit
471d7ff8

 ("powerpc/64s: Remove POWER4 support").

So drop the check. That makes the "testmode" module parameter unused, so
remove it as well.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20231127111740.1288463-1-mpe@ellerman.id.au


Acked-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>