net: stmmac: xgmac: Enable support for multiple Flexible PPS outputs

stable inclusion
from stable-v6.6.2
commit f93f84b203cd0c612cab9f452dbb3a8d519b21db
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8IW7G

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f93f84b203cd0c612cab9f452dbb3a8d519b21db



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[ Upstream commit db456d90a4c1b43b6251fa4348c8adc59b583274 ]

From XGMAC Core 3.20 and later, each Flexible PPS has individual PPSEN bit
to select Fixed mode or Flexible mode. The PPSEN must be set, or it stays
in Fixed PPS mode by default.
XGMAC Core prior 3.20, only PPSEN0(bit 4) is writable. PPSEN{1,2,3} are
read-only reserved, and they are already in Flexible mode by default, our
new code always set PPSEN{1,2,3} do not make things worse ;-)

Fixes: 95eaf3cd ("net: stmmac: dwxgmac: Add Flexible PPS support")
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Furong Xu <0x1207@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>