bng_en: Allocate stat contexts

bng_en: Allocate stat contexts

Allocate the hardware statistics context with the firmware and
register DMA memory required for ring statistics. This helps the
driver to collect ring statistics provided by the firmware.

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/20250919174742.24969-8-bhargava.marreddy@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>