x86/platform/amd: replace down_timeout() with down_interruptible()

x86/platform/amd: replace down_timeout() with down_interruptible()

Currently hsmp_send_message() uses down_timeout() with a 100ms timeout
to take the semaphore. However __hsmp_send_message(), the content of the
critical section, has a sleep in it. On systems with significantly
delayed scheduling behaviour this may take over 100ms.

Convert this method to down_interruptible(). Leave the error handling
the same as the documentation currently is not specific about what error
is returned.

Previous behaviour: a caller who competes with another caller stuck in
the critical section due to scheduler delays would receive -ETIME.

New behaviour: a caller who competes with another caller stuck in the
critical section due to scheduler delays will complete successfully.

Reviewed-by: Suma Hegde <suma.hegde@amd.com>
Tested-by: Suma Hegde <suma.hegde@amd.com>
Signed-off-by: Jake Hillion <jake@hillion.co.uk>
Link: https://lore.kernel.org/r/20250605-amd-hsmp-v2-2-a811bc3dd74a@hillion.co.uk
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>