Update f_mtp.h kernel header

Driver has changed to support transferring > 4 gigabyte files

Change-Id: I9ddca13e8e906a403fe84c9af27ec1fab565be77
Signed-off-by: Mike Lockwood <lockwood@android.com>
diff --git a/libc/kernel/common/linux/usb/f_mtp.h b/libc/kernel/common/linux/usb/f_mtp.h
index e155e7e..a9e37c2 100644
--- a/libc/kernel/common/linux/usb/f_mtp.h
+++ b/libc/kernel/common/linux/usb/f_mtp.h
@@ -21,7 +21,7 @@
 
  loff_t offset;
 
- size_t length;
+ int64_t length;
 };
 
 struct mtp_event {