Compared to our previous 20181218 firmware this updates
polaris12 (rx550, wx2100 etc) and adds picasso, raven2 and vega20.
Needed for a planned backport of picasso support.
I tried the latest 20190618 release on vega10 (Vega 56) but that
currently hangs on boot with our linux 4.19 based amdgpu:
amdgpu_device_resize_fb_bar: stub
amdgpu: [powerplay] Failed message: 0x4, input parameter: 0x10, error code: 0xffffffff
WARNING ring->wptr % 2 || count % 2 failed at /usr/src/sys/dev/pci/drm/amd/amdgpu/uvd_v7_0.c:1387
ok patrick@ sthen@
c66f24615e