powerpc/64s: Add CPU_FTRS_POWER9_DD2_2 to CPU_FTRS_ALWAYS mask

CPU_FTRS_POWER9_DD2_2 is missing from CPU_FTRS_ALWAYS.

That doesn't cause any bug, because CPU_FTRS_POWER9_DD2_2 adds new bits
that don't appear in other values, so when anded with the other masks
the result is the same.

But for consistency we should have all values in the CPU_FTRS_ALWAYS
mask, so that the logic is robust against the values being changed in
future.

Fixes: b5af4f27 ("powerpc: Add CPU feature bits for TM bug workarounds on POWER9 v2.2")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220519122205.746276-1-mpe@ellerman.id.au