iwlwifi: pcie: normally grab NIC access for inflight-hcmd

iwlwifi: pcie: normally grab NIC access for inflight-hcmd

We currently have a special, separate, code path to acquire NIC
access for the in-flight host-command workaround on 7000 series
hardware. However, the normal code path here has grown a number
of additional workarounds/semantics over time, such as reprobing
the device if things fail.

Rather than try to replicate any of this logic, call the normal
grab_nic_access logic for the workaround.

This changes the spinlock to _bh, but that's OK since it's just
redundant, we already have soft-IRQs disabled when we get here,
and so didn't (have to) do it again. Since it's only for commands
there's however no point in making the code more complex just to
not use _bh here.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210330162204.d196fc6ffb23.Idc1ce3ce9fed9178beee7e5409bc669f79b06a0d@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>