crypto/nx: Rename nx-842-pseries file name to nx-common-pseries

Rename nx-842-pseries.c to nx-common-pseries.c to add code for new
GZIP compression type. The actual functionality is not changed in
this patch.

Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1fcf672209a14ea8944bd3e49c8a7381c8f450f8.camel@linux.ibm.com