1. fixup time consuming on glclear, cause by dri2
2. fixup mmap failed, pixmap egl image must use gbm map
3. Use env RK_MALI_SURFACELESS_DISABLE to disable EGL_KHR_surfaceless_context
Signed-off-by: Li Huang <putin.li@rock-chips.com>
Change-Id: I099343c4f82872420dfb34c3926beb6fa1ec0753