net: stmmac: remove extra newline from descriptors display

One newline per line should be enough. Reduce the verbosity of
descriptors dump.

Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Link: https://lore.kernel.org/r/444f3b1dd409fdb14ed2a1ae7679a86b110dadcd.1700372381.git.baruch@tkos.co.il


Signed-off-by: Paolo Abeni <pabeni@redhat.com>