radv: ignore pInheritanceInfo for primary command buffers

From the Vulkan spec:
"If this is a primary command buffer, then this value is ignored."

CC: <mesa-stable@lists.freedesktop.org>
Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
(cherry picked from commit ba5e25ed)