[vulkan] Search for BGRA8 instead of RGBA8

I guess nvidia gives a non-srgb format as the first in the list, but my
laptop gives an srgb format first, thus the unexpected difference in
rendering brightness. Hard-coding BGRA isn't any better, but it will do
for now.

libs/video/renderer/vulkan/swapchain.c

@@ -93,7 +93,7 @@ QFV_CreateSwapchain (vulkan_ctx_t *ctx, VkSwapchainKHR old_swapchain)
 	ifuncs->vkGetPhysicalDeviceSurfaceFormatsKHR (physDev,
 												  ctx->surface,
 												  &numFormats, formats);
-	VkSurfaceFormatKHR useFormat = {VK_FORMAT_R8G8B8A8_UNORM,
+	VkSurfaceFormatKHR useFormat = {VK_FORMAT_B8G8R8A8_UNORM,
 									VK_COLOR_SPACE_SRGB_NONLINEAR_KHR};
 	if (numFormats > 1) {
 		uint32_t i;