USB: change the way we initialize format strings

Changing initialization from

	static const char *string = "blah";

to

	static const char string[] = "blah";

saves us one pointer per each string.

Signed-off-by: Dmitry Torokhov <dtor@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>