bnxt_en: Refactor RX/RX AGG ring parameters setup for P5_PLUS

bnxt_en: Refactor RX/RX AGG ring parameters setup for P5_PLUS

There is some common code for setting up RX and RX AGG ring allocation
parameters for P5_PLUS chips.  Refactor the logic into a new function.

Reviewed-by: Hongguang Gao <hongguang.gao@broadcom.com>
Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Link: https://patch.msgid.link/20250213011240.1640031-7-michael.chan@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>