resource: constify arg to resource_size() and resource_type()

resource_size() doesn't change the resource it operates on, so the res
parameter can be marked const.  Same for resource_type().

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>