The module parameter is read-only since changing mode after loading
isn't going to work.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

--- a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c	2014-07-18 08:42:54.028654483 -0700
+++ b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c	2014-07-18 08:42:54.028654483 -0700
@@ -721,7 +721,7 @@ igbuio_pci_exit_module(void)
 module_init(igbuio_pci_init_module);
 module_exit(igbuio_pci_exit_module);
 
-module_param(intr_mode, charp, S_IRUGO | S_IWUSR);
+module_param(intr_mode, charp, S_IRUGO);
 MODULE_PARM_DESC(intr_mode,
 "igb_uio interrupt mode (default=msix):\n"
 "    " RTE_INTR_MODE_MSIX_NAME "       Use MSIX interrupt\n"