net: phy: dp83822: Fix null pointer access on DP83825/DP83826 devices

stable inclusion
from stable-v5.10.168
commit 362a2f5531dc0e5b0b5b3e3a541000dbffa75461
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7URR4

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=362a2f5531dc0e5b0b5b3e3a541000dbffa75461



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[ Upstream commit 422ae7d9 ]

The probe() function is only used for the DP83822 PHY, leaving the
private data pointer uninitialized for the smaller DP83825/26 models.
While all uses of the private data structure are hidden in 82822 specific
callbacks, configuring the interrupt is shared across all models.
This causes a NULL pointer dereference on the smaller PHYs as it accesses
the private data unchecked. Verifying the pointer avoids that.

Fixes: 5dc39fd5 ("net: phy: DP83822: Add ability to advertise Fiber connection")
Signed-off-by: Andre Kalb <andre.kalb@sma.de>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/Y9FzniUhUtbaGKU7@pc6682


Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: zhaoxiaoqiang11 <zhaoxiaoqiang11@jd.com>