Revert "iwlwifi: pcie: New RBD allocation model"

This reverts commit 5f17570354f91275b0a37a4da33d29a2ab57d32e.

This patch introduced a high latency in buffer allocation
under extreme load. This latency caused a firmwre crash.
The same scenario works fine with this patch reverted.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

diff --cc drivers/net/wireless/iwlwifi/iwl-fh.h
Simple merge

diff --cc drivers/net/wireless/iwlwifi/pcie/internal.h
Simple merge

diff --cc drivers/net/wireless/iwlwifi/pcie/rx.c
Simple merge