drm/i915/gt: add missing new-line to GT_TRACE

Trace requires new-line at the end of message (in opposition to printk),
otherwise trace dump becomes messy.

Signed-off-by: Andrzej Hajda <andrzej.hajda@intel.com>
Acked-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231115-eols-v1-1-d47a2f52b807@intel.com