powerpc/perf: Fix Power9 test_adder fields

powerpc/perf: Fix Power9 test_adder fields

Commit 08907bd080e27 ('powerpc/perf: Add restrictions to PMC5 in power9 DD1')
was added to restrict the use of PMC5 in Power9 DD1. Intention was to disable
the use of PMC5 using raw event code. But instead of updating the
power9_isa207_pmu structure (used on DD1), the commit incorrectly updated the
power9_pmu structure. Fix it.

Fixes: 08907bd080e2 ("powerpc/perf: Add restrictions to PMC5 in power9 DD1")
Reported-by: Shriya <shriyak@linux.vnet.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Tested-by: Shriya <shriyak@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>