iwlwifi: pcie: validate RX descriptor length

Validate the maximum RX descriptor length against the size
of the buffers we gave the device - if it doesn't fit then
the hardware messed up.

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.20201209231352.6378fb435cc0.Ib07485f3dc5999c74b03f21e7a808c50a05e353c@changeid


Signed-off-by: Luca Coelho <luciano.coelho@intel.com>