usb: typec: tcpm: fix the PD disabled case

If the PD is disabled for the port, port->pds will be left as NULL,
which causes the following crash during caps intilisation. Fix the
crash.

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
Call trace:
 tcpm_register_port+0xaec/0xc44
 qcom_pmic_typec_probe+0x1a4/0x254
 platform_probe+0x68/0xc0
 really_probe+0x148/0x2ac
 __driver_probe_device+0x78/0x12c
 driver_probe_device+0xd8/0x160
Bluetooth: hci0: QCA Product ID   :0x0000000a
 __device_attach_driver+0xb8/0x138
 bus_for_each_drv+0x80/0xdc
Bluetooth: hci0: QCA SOC Version  :0x40020150
 __device_attach+0x9c/0x188
 device_initial_probe+0x14/0x20
 bus_probe_device+0xac/0xb0
 deferred_probe_work_func+0x8c/0xc8
 process_one_work+0x1ec/0x51c
 worker_thread+0x1ec/0x3e4
 kthread+0x120/0x124
 ret_from_fork+0x10/0x20

Fixes: cd099cde ("usb: typec: tcpm: Support multiple capabilities")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20240113-pmi632-typec-v2-5-182d9aa0a5b3@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/typec/tcpm/tcpm.c

@@ -6847,7 +6847,8 @@ struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)
 	if (err)
 		goto out_role_sw_put;
 
-	port->typec_caps.pd = port->pds[0];
+	if (port->pds)
+		port->typec_caps.pd = port->pds[0];
 
 	port->typec_port = typec_register_port(port->dev, &port->typec_caps);
 	if (IS_ERR(port->typec_port)) {