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

This reverts commit e279bf8e 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.  It's not a "real" break, and
we can work around it, but this really does not affect Android systems,
so it's safe to drop for now.

Bug: 161946584
Change-Id: Ic12e606a51d05425d81a81d520b800bc24c6eac4
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>