Merge branch 'net-stmmac-Couple-of-debug-prints-improvements'

Florian Fainelli says:

====================
net: stmmac: Couple of debug prints improvements

While working on a particular problem, I had to turn on debug prints and found
them to be useful, but could deserve some improvements in order to help debug
situations.
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Signed-off-by: David S. Miller <davem@davemloft.net>