ata: libahci_platform: Do not set mask_port_map when not needed

Commit 8c87215 ("ata: libahci_platform: support non-consecutive
port numbers") modified ahci_platform_get_resources() to allow
identifying the ports of a controller that are defined as child nodes of
the controller node in order to support non-consecutive port numbers (as
defined by the platform device tree).

However, this commit also erroneously sets bit 0 of
hpriv->mask_port_map when the platform devices tree does not define port
child nodes, to match the fact that the temporary default number of
ports used in that case is 1 (which is also consistent with the fact
that only index 0 of hpriv->phys[] is initialized with the call to
ahci_platform_get_phy(). But doing so causes ahci_platform_init_host()
to initialize and probe only the first port, even if this function
determines that the controller has in fact multiple ports using the
capability register of the controller (through a call to
ahci_nr_ports()). This can be seen with the ahci_mvebu driver (Armada
385 SoC) with the second port declared as "dummy":

ahci-mvebu f10a8000.sata: masking port_map 0x3 -> 0x1
ahci-mvebu f10a8000.sata: AHCI vers 0001.0000, 32 command slots, 6 Gbps, platform mode
ahci-mvebu f10a8000.sata: 1/2 ports implemented (port mask 0x1)
ahci-mvebu f10a8000.sata: flags: 64bit ncq sntf led only pmp fbs pio slum part sxs
scsi host0: ahci-mvebu
scsi host1: ahci-mvebu
ata1: SATA max UDMA/133 mmio [mem 0xf10a8000-0xf10a9fff] port 0x100 irq 40 lpm-pol 0
ata2: DUMMY

Fix this issue by removing setting bit 0 of hpriv->mask_port_map when
the platform device tree does not define port child nodes.

Reported-by: Klaus Kudielka <klaus.kudielka@gmail.com>
Fixes: 8c87215 ("ata: libahci_platform: support non-consecutive port numbers")
Tested-by: Klaus Kudielka <klaus.kudielka@gmail.com>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Acked-by: Josua Mayer <josua@solid-run.com>
Link: https://lore.kernel.org/r/20250207232915.1439174-1-dlemoal@kernel.org
Signed-off-by: Niklas Cassel <cassel@kernel.org>

Author: damien-lemoal

drivers/ata/libahci_platform.c

@@ -651,8 +651,6 @@ struct ahci_host_priv *ahci_platform_get_resources(struct platform_device *pdev,
 		 * If no sub-node was found, keep this for device tree
 		 * compatibility
 		 */
-		hpriv->mask_port_map |= BIT(0);
-
 		rc = ahci_platform_get_phy(hpriv, 0, dev, dev->of_node);
 		if (rc)
 			goto err_out;