USB: Use core_param.

Found this when I changed args to __module_param_call.  We now have
core_param for exactly this.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
---
 drivers/usb/core/usb.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff -r 65aebfe44ef1 drivers/usb/core/usb.c
--- a/drivers/usb/core/usb.c	Wed Nov 19 22:47:52 2008 +1030
+++ b/drivers/usb/core/usb.c	Wed Nov 19 23:58:08 2008 +1030
@@ -963,7 +963,7 @@
 EXPORT_SYMBOL_GPL(usb_buffer_unmap_sg);
 
 /* format to disable USB on kernel command line is: nousb */
-__module_param_call("", nousb, param_set_bool, param_get_bool, &nousb, 0444);
+core_param(nousb, nousb, bool, 0444);
 
 /*
  * for external read access to <nousb>