drm/i915/psr: remove unused lines_to_wait vbt info

The lines_to_wait info from VBT is never used. Remove.

Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Jouni Högander <jouni.hogander@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220112112715.1234366-1-jani.nikula@intel.com