selftests/powerpc: Fix ptrace-pkey for default execute permission change

The test case assumes execute-permissions of unallocated keys are
enabled by default, which is incorrect.
Reviewed-by: NThiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: NRam Pai <linuxram@us.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

tools/testing/selftests/powerpc/ptrace/ptrace-pkey.c

@@ -104,6 +104,10 @@ static int child(struct shared_info *info)
 
 	if (disable_execute)
 		info->expected_iamr |= 1ul << pkeyshift(pkey1);
+	else
+		info->expected_iamr &= ~(1ul << pkeyshift(pkey1));
+
+	info->expected_iamr &= ~(1ul << pkeyshift(pkey2) | 1ul << pkeyshift(pkey3));
 
 	info->expected_uamor |= 3ul << pkeyshift(pkey1) |
 				3ul << pkeyshift(pkey2);