- bus_dmamap fixes, with checks against NULL
- move the rings' allocation code later in iwi_attach() to avoid NULL pointer
dereference if allocation fails
- avoid double free() in case of failure during attach. If an allocation fails,
do not free the ring directly, as it is handled by iwi_detach()
- only set ring->count for RX/TX rings when ring allocation is successful, or
else the for loop during detach will fail with a NULL dereference.
- call pci_intr_disestablish() if iwi_reset() fails during attach; driver is
in an incoherent state, interrupt handler should not be used.
Proposed by me on tech-net@, approved by christos@. Compiled and tested
with GENERIC and XEN3_DOM0 kernels.
96f9080096