net: phy: adin1100: Fix software power-down ready condition

net: phy: adin1100: Fix software power-down ready condition

Value CRSM_SFT_PD written to Software Power-Down Control Register
(CRSM_SFT_PD_CNTRL) is 0x01 and therefor different to value
CRSM_SFT_PD_RDY (0x02) read from System Status Register (CRSM_STAT) for
confirmation powerdown has been reached.

The condition could have only worked when disabling powerdown
(both 0x00), but never when enabling it (0x01 != 0x02).

Result is a timeout, like so:

    $ ifdown eth0
    macb f802c000.ethernet eth0: Link is Down
    ADIN1100 f802c000.ethernet-ffffffff:01: adin_set_powerdown_mode failed: -110
    ADIN1100 f802c000.ethernet-ffffffff:01: adin_set_powerdown_mode failed: -110

Fixes: 7eaf9132996a ("net: phy: adin1100: Add initial support for ADIN1100 industrial PHY")
Signed-off-by: Alexander Dahl <ada@thorsis.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://patch.msgid.link/20251119124737.280939-2-ada@thorsis.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>