USB: Debugfs: Fix compilation issues when debugfs is disabled

When we disable debugfs some of the function driver does not
handle those error properly so we see error of kind variable
undeclared, too many arguements to function. This fixes all
these obseved issue

CRs-fixed: 551713
Change-Id: I18e183fd2381abf680df6c360d6eab477cdb5b76
Signed-off-by: Tarun Gupta <tarung@codeaurora.org>