net: ionic: Provide doorbell and CMB region information

net: ionic: Provide doorbell and CMB region information

The RDMA device needs information of controller memory bar and
doorbell capability to share with user context. Discover CMB regions
and express doorbell capabilities on device init.

Reviewed-by: Shannon Nelson <shannon.nelson@amd.com>
Co-developed-by: Pablo Cascón <pablo.cascon@amd.com>
Signed-off-by: Pablo Cascón <pablo.cascon@amd.com>
Co-developed-by: Allen Hubbe <allen.hubbe@amd.com>
Signed-off-by: Allen Hubbe <allen.hubbe@amd.com>
Signed-off-by: Abhijit Gangurde <abhijit.gangurde@amd.com>
Link: https://patch.msgid.link/20250903061606.4139957-7-abhijit.gangurde@amd.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>