phy: cadence-torrent: Check return value on register read

BugLink: https://bugs.launchpad.net/bugs/2083196

[ Upstream commit 967969cf594ed3c1678a9918d6e9bb2d1591cbe9 ]

cdns_torrent_dp_set_power_state() does not consider that ret might be
overwritten. Add return value check of regmap_read_poll_timeout() after
register read in cdns_torrent_dp_set_power_state().

Fixes: 5b16a790f1 ("phy: cadence-torrent: Reorder few functions to remove function declarations")
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
Reviewed-by: Roger Quadros <rogerq@kernel.org>
Link: https://lore.kernel.org/r/20240702032042.3993031-1-make24@iscas.ac.cn
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Portia Stephens <portia.stephens@canonical.com>
Signed-off-by: Roxana Nicolescu <roxana.nicolescu@canonical.com>

drivers/phy/cadence/phy-cadence-torrent.c

@@ -1154,6 +1154,9 @@ static int cdns_torrent_dp_set_power_state(struct cdns_torrent_phy *cdns_phy,
 	ret = regmap_read_poll_timeout(regmap, PHY_PMA_XCVR_POWER_STATE_ACK,
 				       read_val, (read_val & mask) == value, 0,
 				       POLL_TIMEOUT_US);
+	if (ret)
+		return ret;
+
 	cdns_torrent_dp_write(regmap, PHY_PMA_XCVR_POWER_STATE_REQ, 0x00000000);
 	ndelay(100);