Update to 2.4.50:

libdrm 2.4.50 has been released. It fixes a critical bug for Radeon
Southern Islands GPUs.

Keith Packard (1):
      intel: Track known prime buffers for re-use

Marek Ol邸叩k (1):
      Bump the version to 2.4.50

Michel D辰nzer (1):
      radeon: Update unaligned offset for 2D->1D tiling transition on SI

(wiz)