s390/ap/zcrypt: New xflag parameter

s390/ap/zcrypt: New xflag parameter

Introduce a new flag parameter for the both cprb send functions
zcrypt_send_cprb() and zcrypt_send_ep11_cprb(). This new
xflags parameter ("execution flags") shall be used to provide
execution hints and flags for this crypto request.

There are two flags implemented to be used with these functions:
* ZCRYPT_XFLAG_USERSPACE - indicates to the lower layers that
  all the ptrs address userspace. So when construction the ap msg
  copy_from_user() is to be used. If this flag is NOT set, the ptrs
  address kernel memory and thus memcpy() is to be used.
* ZCRYPT_XFLAG_NOMEMALLOC - indicates that this task must not
  allocate memory which may be allocated with io operations.

For the AP bus and zcrypt message layer this means:
* The ZCRYPT_XFLAG_USERSPACE is mapped to the already existing
  bool variable "userspace" which is propagated to the zcrypt
  proto implementations.
* The ZCRYPT_XFLAG_NOMEMALLOC results in setting the AP flag
  AP_MSG_FLAG_MEMPOOL when the AP msg buffer is initialized.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Holger Dengler <dengler@linux.ibm.com>
Link: https://lore.kernel.org/r/20250424133619.16495-6-freude@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>