autosuspend_inited flag set even if initialization fails

Prevents possible SIGSEGV on second autosuspend_enable attempt when
first intialization attempt fails.  autosuspend_inited should only
be set once autosuspend_ops has been assigned.

Consider the first call to autosuspend_enable().
autosuspend_init() sets its inited flag to true, and attempts to
set autosuspend_ops.  If all the other autosuspend_*_init() attempts
fail, autosuspend_init() returns -1, which autosuspend_enable()
will return as a failure.  A second call to autosuspend_enable()
will check autosuspend_init() and see that autosuspend has already
been initialized.  It will attempt to access autosuspend_ops, which
were not set in the first initialization attempt, causing a SIGSEGV.

Change-Id: Ib2d3ee62fee4c3b6d0323e5b7f3709a23c6b923f