Hantro VPU driver in Linux kernel 5.4

The latest kernel release (5.4) introduces support for H.264 decoding on RK3288, and also VP8 decoding on RK3288 and RK3399. Popular RK3288-based platforms include ASUS Chromebook Flip and ASUS C201 Chromebook, so this change brings Chromebooks one step closer to running upstream, reducing the upstream/downstream gap.