platform/x86/amd/hsmp: Define a struct to hold mailbox regs

platform/x86/amd/hsmp: Define a struct to hold mailbox regs

Define struct hsmp_mbaddr_info with register offsets and populate
them during probe, which avoids the usage of macros in core functions.

During ACPI probe, the same fields can be populated from ACPI table.

Also move plat dev init to a static function.

Signed-off-by: Suma Hegde <suma.hegde@amd.com>
Signed-off-by: Naveen Krishna Chatradhi <nchatrad@amd.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20240106022532.1746932-4-suma.hegde@amd.com
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>