USB: Make file operations structs in drivers/usb const.

Making structs const prevents accidental bugs and with the proper debug
options they're protected against corruption.

Signed-off-by: Luiz Fernando N. Capitulino <lcapitulino@mandriva.com.br>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/host/isp116x-hcd.c b/drivers/usb/host/isp116x-hcd.c
index 8c6b38a..a72e041 100644
--- a/drivers/usb/host/isp116x-hcd.c
+++ b/drivers/usb/host/isp116x-hcd.c
@@ -1207,7 +1207,7 @@
 	return single_open(file, isp116x_show_dbg, inode->i_private);
 }
 
-static struct file_operations isp116x_debug_fops = {
+static const struct file_operations isp116x_debug_fops = {
 	.open = isp116x_open_seq,
 	.read = seq_read,
 	.llseek = seq_lseek,