xsm: allow relevant permission during migrate and gpu-passthrough.

xsm: allow relevant permission during migrate and gpu-passthrough.

During guest migrate allow permission to prevent
spurious page faults.
Prevents these errors:
d73: Non-privileged (73) attempt to map I/O space 00000000

avc: denied  { set_misc_info } for domid=0 target=11
scontext=system_u:system_r:dom0_t
tcontext=system_u:system_r:domU_t tclass=domain

GPU passthrough for hvm guest:
avc:  denied  { send_irq } for domid=0 target=10
scontext=system_u:system_r:dom0_t
tcontext=system_u:system_r:domU_t tclass=hvm

Signed-off-by: Anshul Makkar <anshul.makkar@citrix.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>