selftests/powerpc/dexcr: Add -no-pie to hashchk tests

The hashchk tests want to verify that the hash key is changed over exec.
It does so by calculating hashes at the same address across an exec.
This is made simpler by disabling PIE functionality, so we can
re-execute ourselves and be using the same addresses in the child.

While -fno-pie is already added, -no-pie is also required.

Fixes: bdb07f35 ("selftests/powerpc/dexcr: Add hashst/hashchk test")
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240417112325.728010-2-bgray@linux.ibm.com