fix spelling in main directory

Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
diff --git a/vl.c b/vl.c
index a50842b..5372a96 100644
--- a/vl.c
+++ b/vl.c
@@ -820,7 +820,7 @@
         /* Allowed boot devices are:
          * a-b: floppy disk drives
          * c-f: IDE disk drives
-         * g-m: machine implementation dependant drives
+         * g-m: machine implementation dependent drives
          * n-p: network devices
          * It's up to each machine implementation to check if the given boot
          * devices match the actual hardware implementation and firmware