iwlwifi: pcie: allocate rb_stts's for all queues in one place

AX210 devices assume that the (DRAM) addresses of the rb_stts's for
the different queues are continuous.
So allocate the rb_stts's for all the Rx queues in one place.

Signed-off-by: Shaul Triebitz <shaul.triebitz@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>