A small uvlong vs vlong fix in ums.h

A change to usb lib to make usbd and all drivers bind devusb if /dev/usb
is not there. A 9fan started usbd and then changed the ns so that usbd could
not open new endpoints. I think this may help.

Reference: /n/sources/patch/applied/usbfixes
Date: Fri May 29 18:20:56 CES 2009
Signed-off-by: nemo@lsub.org

--- /sys/src/cmd/usb/disk/ums.h	Fri May 29 18:05:00 2009
+++ /sys/src/cmd/usb/disk/ums.h	Fri May 29 18:04:57 2009
@@ -50,7 +50,7 @@
 {
 	ScsiReq;
 	uvlong	blocks;
-	uvlong	capacity;
+	vlong	capacity;
 	uchar 	rawcmd[10];
 	uchar	phase;
 	char	*inq;
--- /sys/src/cmd/usb/lib/dev.c	Fri May 29 18:05:04 2009
+++ /sys/src/cmd/usb/lib/dev.c	Fri May 29 18:05:02 2009
@@ -33,6 +33,8 @@
 	Usbdev *ud;
 	char name[40];
 
+	if(access("/dev/usb", AEXIST) < 0 && bind("#u", "/dev", MBEFORE) < 0)
+		return nil;
 	if(d->cfd < 0 || d->usb == nil){
 		werrstr("device not configured");
 		return nil;
@@ -91,6 +93,8 @@
 	Dev *d;
 	int l;
 
+	if(access("/dev/usb", AEXIST) < 0 && bind("#u", "/dev", MBEFORE) < 0)
+		return nil;
 	d = emallocz(sizeof(Dev), 1);
 	incref(d);