bng_en: Initialise core resources

bng_en: Initialise core resources

Add initial settings to all core resources, such as
the RX, AGG, TX, CQ, and NQ rings, as well as the VNIC.
This will help enable these resources in future patches.

Signed-off-by: Bhargava Marreddy <bhargava.marreddy@broadcom.com>
Reviewed-by: Vikas Gupta <vikas.gupta@broadcom.com>
Reviewed-by: Rajashekar Hudumula <rajashekar.hudumula@broadcom.com>
Link: https://patch.msgid.link/20250919174742.24969-6-bhargava.marreddy@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>