serial: icom: Convert PCIBIOS_* return codes to errnos

icom_probe() uses pci_read_config_dword() that returns PCIBIOS_*
codes. The return code is returned from the probe function as is but
probe functions should return normal errnos. A proper implementation
can be found in drivers/leds/leds-ss4200.c

Convert PCIBIOS_* return codes using pcibios_err_to_errno() into
normal errno before returning them.

Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
Link: https://patch.msgid.link/20251117040710.1544-1-vulab@iscas.ac.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/icom.c

@@ -1723,6 +1723,7 @@ static int icom_probe(struct pci_dev *dev,
 	retval = pci_read_config_dword(dev, PCI_COMMAND, &command_reg);
 	if (retval) {
 		dev_err(&dev->dev, "PCI Config read FAILED\n");
+		retval = pcibios_err_to_errno(retval);
 		goto probe_exit0;
 	}