radv: implement a workaround for VK_EXT_conditional_rendering

radv: implement a workaround for VK_EXT_conditional_rendering

Per the Vulkan spec 1.1.107, the predicate is a 32-bit value. Though
the AMD hardware treats it as a 64-bit value which means it might
fail to discard.

I don't know why this extension has been drafted like that but this
definitely not fit with AMD. The hardware doesn't seem to support
a 32-bit value for the predicate, so we need to implement a workaround.

This fixes an issue when DXVK enables conditional rendering with RADV,
this also fixes the Sasha conditionalrender demo.

Fixes: e45ba51ea45 ("radv: add support for VK_EXT_conditional_rendering")
Reported-by: Philip Rebohle <philip.rebohle@tu-dortmund.de>
Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>