anv/cmd_buffer: Apply flush operations prior to executing secondaries

This fixes rendering issues in the Vulkan port of skia on some hardware.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: "13.0 17.0" <mesa-stable@lists.freedesktop.org>
(cherry picked from commit 01a65dc43be3a4bf6b8a901586f7222218f4b6b3)
[Andres Gomez: resolve trivial conflicts]
Signed-off-by: Andres Gomez <agomez@igalia.com>

Conflicts:
	src/intel/vulkan/genX_cmd_buffer.c
1 file changed