powerpc/kcsan: Add exclusions from instrumentation

Exclude various incompatible compilation units from KCSAN
instrumentation.

Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230206021801.105268-2-rmclure@linux.ibm.com