drm/i915/gem: Fix a lockdep warning the __i915_gem_is_lmem() function

Somehow we managed to invert the test for i915_gem_object_evictable(),
which causes a warning in DG1 BAT, igt@debugfs_test@read_all_entries.

Fix the lock check to only warn if the object *is* indeed evictable and
not protected from eviction by fences.

Cc: Matthew Brost <matthew.brost@intel.com>
Fixes: 91160c83

 ("drm/i915: Take pinning into account in __i915_gem_object_is_lmem")

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210922083807.888206-2-thomas.hellstrom@linux.intel.com