net: stmmac: Rework coalesce timer and fix multi-queue races

This follows David Miller advice and tries to fix coalesce timer in
multi-queue scenarios.

We are now using per-queue coalesce values and per-queue TX timer.

Coalesce timer default values was changed to 1ms and the coalesce frames
to 25.

Tested in B2B setup between XGMAC2 and GMAC5.

Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Fixes: 	ce736788 ("net: stmmac: adding multiple buffers for TX")
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Jerome Brunet <jbrunet@baylibre.com>
Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Joao Pinto <jpinto@synopsys.com>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>