anv: Fix FlushMappedMemoryRanges for odd mmap offsets
When the client calls vkMapMemory(), we have to align the requested offset down to the nearest page or else the map will fail. On platforms where we have DRM_IOCTL_I915_GEM_MMAP_OFFSET, we always map the whole buffer. In either case, the original map may start before the requested offset and we need to take that into account when we clflush. Cc: mesa-stable@lists.freedesktop.org Reviewed-by:Paulo Zanoni <paulo.r.zanoni@intel.com> Part-of: <mesa/mesa!13610>