platform/x86/amd/hsmp: Move hsmp_test to probe

platform/x86/amd/hsmp: Move hsmp_test to probe

This is in advance to supporting ACPI based probe.

In case of non-ACPI driver, hsmp_test() can be
performed either in plat init() or in probe().

however, in case of ACPI probing, hsmp_test() cannot
be called in init(), as the mailbox reg offsets and
base addresses are read from ACPI table in the probe().

Hence, move hsmp_test() to probe as preparation for
ACPI support.

Also use hsmp_send_message() directly in hsmp_test()
as the semaphore is already initialized in probe.

Signed-off-by: Suma Hegde <suma.hegde@amd.com>
Signed-off-by: Naveen Krishna Chatradhi <nchatrad@amd.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20240106022532.1746932-1-suma.hegde@amd.com
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>