[PATCH 3/3] usb: early: xhci-dbc: Fix xdbc number parsing

[Peter Zijlstra <peterz@infradead.org>]

kstrtoul() assumes the string contains the number only and is \0
terminated, this is not the case, as such things like:

	earlyprintk=xdbc1,keep

go completely sideways. Use simple_strtoul() instead.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 drivers/usb/early/xhci-dbc.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/usb/early/xhci-dbc.c
+++ b/drivers/usb/early/xhci-dbc.c
@@ -603,6 +603,7 @@ int __init early_xdbc_parse_parameter(ch
 {
 	unsigned long dbgp_num = 0;
 	u32 bus, dev, func, offset;
+	char *e;
 	int ret;
 
 	if (!early_pci_allowed())
@@ -613,8 +614,11 @@ int __init early_xdbc_parse_parameter(ch
 	if (xdbc.xdbc_reg)
 		return 0;
 
-	if (*s && kstrtoul(s, 0, &dbgp_num))
-		dbgp_num = 0;
+	if (*s) {
+	       dbgp_num = simple_strtoul(s, &e, 10);
+	       if (s == e)
+		       dbgp_num = 0;
+	}
 
 	pr_notice("dbgp_num: %lu\n", dbgp_num);