drm/xe/vf: Create contexts for CCS read write

Create two LRCs to handle CCS meta data read / write from CCS pool in the
VM. Read context is used to hold GPU instructions to be executed at save
time and write context is used to hold GPU instructions to be executed at
the restore time.

Allocate batch buffer pool using suballocator for both read and write
contexts.

Migration framework is reused to create LRCAs for read and write.

Signed-off-by: Satyanarayana K V P <satyanarayana.k.v.p@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Link: https://lore.kernel.org/r/20250722120506.6483-2-satyanarayana.k.v.p@intel.com