Revert "usb: roles: fix NULL pointer issue when put module's reference"

This reverts commit 01582168 which is
commit 1c9be138 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: I092d81a7ad00ebe0d0c16509b5789ea0b7de29e4
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>