ionic: clean dbpage in de-init

Since the kern_dbpage gets set up in ionic_lif_init() and that
function's error path will clean it if needed, the kern_dbpage
on teardown should be cleaned in ionic_lif_deinit(), not in
ionic_lif_free().  As it is currently we get a double call
to iounmap() on kern_dbpage if the PCI ionic fails setting up
the lif.  One example of this is when firmware isn't responding
to AdminQ requests and ionic's first AdminQ call fails to
setup the NotifyQ.

Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Joe Damato <joe@dama.to>
Signed-off-by: David S. Miller <davem@davemloft.net>