net: stmmac: fix INTR TBU status affecting irq count statistic

net: stmmac: fix INTR TBU status affecting irq count statistic

BugLink: https://bugs.launchpad.net/bugs/1946788
[ Upstream commit 1975df880b959e30f28d66148a12d77b458abd76 ]

DMA channel status "Transmit buffer unavailable(TBU)" bit is not
considered as a successful dma tx. Hence, it should not affect
all the irq count statistic.

Fixes: 1103d3a5531c ("net: stmmac: dwmac4: Also use TBU interrupt to clean TX path")
Signed-off-by: Voon Weifeng <weifeng.voon@intel.com>
Signed-off-by: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>