[Intel-gfx] [Patch] mutiple ring buffer patch for libdrm

[Zou, Nanhai]

Hi,
	This is the multiple ring buffer patch for libdrm.
Basically it exposed the execbuffer2 flag to user space application.

Signed-off-by: Xiang Hai hao <haihao.xiang at intel.com>
Signed-off-by: Zou Nan hai <nanhai.zou at intel.com>