forked from Mirrors/opensbi

The discovery of P2A doorbell system MSI index is now through RPMI shared memory DT node so remove p2a_db_index from RPMI system MSI attributes and access it as a mailbox channel attribute. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Link: https://lore.kernel.org/r/20250512083827.804151-5-apatel@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>