s390/appldata: pass parameter list pointer to appldata_asm

In preparation for CONFIG_VMAP_STACK=y move the allocation of the
struct appldata_parameter_list to the caller of appldata_asm().

Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>