s390/zcrypt: Integrate ap_asm.h into include/asm/ap.h.

Move all the inline functions from the ap bus header
file ap_asm.h into the in-kernel api header file
arch/s390/include/asm/ap.h so that KVM can make use
of all the low level AP functions.

Signed-off-by: Harald Freudenberger <freude@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>