platform/x86/amd/pmf: Use memdup_user()

Switch to memdup_user() to overwrite the allocated memory only once
instead of initializing the allocated memory to zero with kzalloc() and
then immediately overwriting it with copy_from_user().

Fixes the following Coccinelle/coccicheck warning reported by
memdup_user.cocci:

	WARNING opportunity for memdup_user

Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Link: https://lore.kernel.org/r/20240527083628.210491-2-thorsten.blum@toblux.com


Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>