[vulkan] Support chained render pass infos

And thus the cube mapped render pass.

include/QF/Vulkan/render.h

@@ -158,6 +158,7 @@ typedef struct qfv_framebufferinfo_s {
 typedef struct qfv_renderpassinfo_s {
 	vec4f_t     color;
 	const char *name;
+	void       *pNext;
 	uint32_t    num_attachments;
 	qfv_attachmentinfo_t *attachments;
 	qfv_framebufferinfo_t framebuffer;

libs/video/renderer/vulkan/rp_main_def.plist

@@ -1147,12 +1147,12 @@ renderpasses = {
 			};
 		};
 	};
-	/*deferred_cube = {
+	deferred_cube = {
 		@inherit = $renderpasses.deferred;
 		@next = (VkRenderPassMultiviewCreateInfo, {
 			viewMasks   = (0x3fu, 0x3fu, 0x3fu, 0x3fu, 0x3fu);
 			viewOffsets = (    0,     0,     0,     0,     0);
 		});
-	};*/
+	};
 };
 };