tty/8250_early: Don't truncate last character of options

The earlier change to use strlcpy uncovered a bug in the options argument length calculation causing last character to be truncated. This makes the actual console to be configured with incorrect baudrate when specifying the console using console=uart,... syntax.

Bug symptom seen in kernel log output:

Kernel command line: console=uart,mmio,0x90000000,115200 Early serial console at MMIO 0x90000000 (options '11520')

which then results in a invalid baud rate 11520 instead of the expected 115200 when the console is switched to ttyS0 later in the boot process.

---
 drivers/tty/serial/8250/8250_early.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

index 721904f..946ddd2 100644
@@ -193,7 +193,8 @@ static int __init parse_options(struct early_serial8250_device *device,
 	if (options) {
 		options++;
 		device->baud = simple_strtoul(options, NULL, 0);
-		length = min(strcspn(options, " "), sizeof(device->options));
+		length = min(strcspn(options, " ") + 1,
+			     sizeof(device->options));
 		strlcpy(device->options, options, length);
 	} else {
 		device->baud = probe_baud(port);

1.8.3.1