drm/xe/svm: Extend MAP range to reduce vma fragmentation

drm/xe/svm: Extend MAP range to reduce vma fragmentation

When DRM_XE_VM_BIND_FLAG_CPU_ADDR_MIRROR is set during VM_BIND_OP_MAP,
the mapping logic now checks adjacent cpu_addr_mirror VMAs with default
attributes and expands the mapping range accordingly. This ensures that
bo_unmap operations ideally target the same area and helps reduce
fragmentation by coalescing nearby compatible VMAs into a single mapping.

Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20251125075628.1182481-4-himal.prasad.ghimiray@intel.com
Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>