net: phy: broadcom: stub c45 read/write for 54810

stable inclusion
from stable-v5.10.192
commit 526d42c558f5133bcf9fff831eb3f2995ef5a7b3
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I933RF

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=526d42c558f5133bcf9fff831eb3f2995ef5a7b3



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[ Upstream commit 096516d0 ]

The 54810 does not support c45. The mmd_phy_indirect accesses return
arbirtary values leading to odd behavior like saying it supports EEE
when it doesn't. We also see that reading/writing these non-existent
MMD registers leads to phy instability in some cases.

Fixes: b14995ac ("net: phy: broadcom: Add BCM54810 PHY entry")
Signed-off-by: Justin Chen <justin.chen@broadcom.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/1691901708-28650-1-git-send-email-justin.chen@broadcom.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>