drm/i915: Update DRIVER_DATE to 20190311

#define DRIVER_NAME		"i915"

#define DRIVER_DESC		"Intel Graphics"

#define DRIVER_DATE		"20190220"

#define DRIVER_TIMESTAMP	1550657146

#define DRIVER_DATE		"20190311"

#define DRIVER_TIMESTAMP	1552292224

/* Use I915_STATE_WARN(x) and I915_STATE_WARN_ON() (rather than WARN() and

 * WARN_ON()) for hw state sanity checks to check for unexpected conditions