drm/xe/oa/uapi: Define and parse OA sync properties

Now that we have laid the groundwork, introduce OA sync properties in the
uapi and parse the input xe_sync array as is done elsewhere in the
driver. Also add DRM_XE_OA_CAPS_SYNCS bit in OA capabilities for userspace.

v2: Fix and document DRM_XE_SYNC_TYPE_USER_FENCE for OA (Matt B)
    Add DRM_XE_OA_CAPS_SYNCS bit to OA capabilities (Jose)

Acked-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241022200352.1192560-3-ashutosh.dixit@intel.com