lavfi: add an avgblur_vulkan filter

This commit adds a fast avgblur Vulkan filter.
This will reset Intel GPUs on Linux due to a known, two-year-old driver bug
(!834 on mesa's gitlab).

configure

@@ -3461,6 +3461,7 @@ ass_filter_deps="libass"
 atempo_filter_deps="avcodec"
 atempo_filter_select="rdft"
 avgblur_opencl_filter_deps="opencl"
+avgblur_vulkan_filter_deps="vulkan libglslang"
 azmq_filter_deps="libzmq"
 blackframe_filter_deps="gpl"
 bm3d_filter_deps="avcodec"

libavfilter/Makefile

@@ -163,6 +163,7 @@ OBJS-$(CONFIG_ATADENOISE_FILTER)             += vf_atadenoise.o
 OBJS-$(CONFIG_AVGBLUR_FILTER)                += vf_avgblur.o
 OBJS-$(CONFIG_AVGBLUR_OPENCL_FILTER)         += vf_avgblur_opencl.o opencl.o \
                                                 opencl/avgblur.o boxblur.o
+OBJS-$(CONFIG_AVGBLUR_VULKAN_FILTER)         += vf_avgblur_vulkan.o vulkan.o
 OBJS-$(CONFIG_BBOX_FILTER)                   += bbox.o vf_bbox.o
 OBJS-$(CONFIG_BENCH_FILTER)                  += f_bench.o
 OBJS-$(CONFIG_BILATERAL_FILTER)              += vf_bilateral.o

libavfilter/allfilters.c

@@ -154,6 +154,7 @@ extern AVFilter ff_vf_ass;
 extern AVFilter ff_vf_atadenoise;
 extern AVFilter ff_vf_avgblur;
 extern AVFilter ff_vf_avgblur_opencl;
+extern AVFilter ff_vf_avgblur_vulkan;
 extern AVFilter ff_vf_bbox;
 extern AVFilter ff_vf_bench;
 extern AVFilter ff_vf_bilateral;