tests/pm_rpm: add gem-evict-pwrite subtest

This triggers a device suspended WARN in the kernel in
gen6_ggtt_insert_entries() while calling the GEM pwrite ioctl.

The sequence is suggested by Daniel.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

lib/igt_aux.h

@@ -31,6 +31,9 @@
 #include <intel_bufmgr.h>
 #include <stdbool.h>
 
+extern drm_intel_bo **trash_bos;
+extern int num_trash_bos;
+
 /* auxialiary igt helpers from igt_aux.c */
 /* generally useful helpers */
 void igt_fork_signal_helper(void);