drm/i915/doc: Convert perf UAPI comments to kerneldoc

Convert the comments for  drm_i915_query_perf_config and
drm_i915_perf_oa_config to kerneldoc so that they will show up in the
generated documentation.  Also correct a couple places that referred to
query_id when they actually meant to refer to query_item.flags.

Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20220414192230.749771-2-matthew.d.roper@intel.com