USB: dwc3: Fix compilation error when debugfs is disabled
USB: dwc3: Fix compilation error when debugfs is disabled

The code does not compile with debugfs disabled. Fix this.

Change-Id: I19b784495b57e7fc0c57b455dd80a63b79177569
Signed-off-by: Olav Haugan <fbf4ddd114d5f0aa83cb721b7dacab8a264ccf22@codeaurora.org>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas