drm/xe/oa: Move functions up so they can be reused for config ioctl

No code changes, only code movement so that functions used during stream
open can be reused for the stream reconfiguration
ioctl (DRM_XE_OBSERVATION_IOCTL_CONFIG).

Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241022200352.1192560-6-ashutosh.dixit@intel.com