drm/i915: remove redundant assignment to variable err

The variable err is being initialized with a value that is never read
and it is being updated later with a new value.  The initialization is
redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200409133107.415812-1-colin.king@canonical.com

drivers/gpu/drm/i915/gem/selftests/i915_gem_object.c

@@ -14,7 +14,7 @@ static int igt_gem_object(void *arg)
 {
 	struct drm_i915_private *i915 = arg;
 	struct drm_i915_gem_object *obj;
-	int err = -ENOMEM;
+	int err;
 
 	/* Basic test to ensure we can create an object */