Revert "xhci: fix debugfs register accesses while suspended"

This reverts commit 3092933b which is
commit 735baf1b upstream.

It breaks the Android kernel abi, so revert it.  If it needs to come
back later, it can do so in an abi-safe way.

Bug: 161946584
Change-Id: Iffb5e2b7efc7235005d07d4b3277a8c6c1930616
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>