selftests/powerpc: Add test case for tlbie vs mtpidr ordering issue

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Some minor fixes to make it build]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190924035254.24612-4-aneesh.kumar@linux.ibm.com