drm/i915/perf: Fix compiler warning for string truncation

drivers/gpu/drm/i915/i915_oa_cflgt3.c: In function ‘i915_perf_load_test_config_cflgt3’:
drivers/gpu/drm/i915/i915_oa_cflgt3.c:87:2: error: ‘strncpy’ output truncated before terminating nul copying 36 bytes from a string of the same length [-Werror=stringop-truncation]

v2: strlcpy

Fixes: 4407eaa9 ("drm/i915/perf: add support for Coffeelake GT3")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180208102403.5587-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_oa_cflgt3.c

@@ -84,9 +84,9 @@ show_test_oa_id(struct device *kdev, struct device_attribute *attr, char *buf)
 void
 i915_perf_load_test_config_cflgt3(struct drm_i915_private *dev_priv)
 {
-	strncpy(dev_priv->perf.oa.test_config.uuid,
+	strlcpy(dev_priv->perf.oa.test_config.uuid,
 		"577e8e2c-3fa0-4875-8743-3538d585e3b0",
-		UUID_STRING_LEN);
+		sizeof(dev_priv->perf.oa.test_config.uuid));
 	dev_priv->perf.oa.test_config.id = 1;
 
 	dev_priv->perf.oa.test_config.mux_regs = mux_config_test_oa;