ANDROID: arm64: kvm: Add new module functions used by s2mpu.

Add functions needed by S2MPU el2 module:
 -pkvm_host_donate_hyp/pkvm_hyp_donate_host: get and return SMPT from
  host kernel.
 -memcpy/memset: common functions used by s2mpu module.
 -hyp_pa: convert hyp address to PA, to get DMA address of SMPT.
 -kern_hyp_va: convert kernel address to hyp VA, used by the
  module to get the VA of SMPTs allocated from the kernel.

Bug: 261857213
Change-Id: Idceccf0ac38444e7f267f50c476b99f01a613372
Signed-off-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>