net: stmmac: fix a possible endless loop

net: stmmac: fix a possible endless loop

BugLink: https://bugs.launchpad.net/bugs/1863588
[ Upstream commit 7d10f0774f9e32aa2f2e012f7fcb312a2ce422b9 ]

It forgot to reduce the value of the variable retry in a while loop
in the ethqos_configure() function. It may cause an endless loop and
without timeout.

Fixes: a7c30e62d4b8 ("net: stmmac: Add driver for Qualcomm ethqos")
Signed-off-by: Dejin Zheng <zhengdejin5@gmail.com>
Acked-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>