radv: fix invalid conversion warnings in vk_format.h

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6013>
diff --git a/src/amd/vulkan/vk_format.h b/src/amd/vulkan/vk_format.h
index 0b62ea7..285de63 100644
--- a/src/amd/vulkan/vk_format.h
+++ b/src/amd/vulkan/vk_format.h
@@ -280,22 +280,22 @@
 	case VK_COMPONENT_SWIZZLE_R:
 		for (x = 0; x < 4; x++)
 			if (chan[x] == 0)
-				return x;
+				return (enum vk_swizzle)x;
 		return VK_SWIZZLE_0;
 	case VK_COMPONENT_SWIZZLE_G:
 		for (x = 0; x < 4; x++)
 			if (chan[x] == 1)
-				return x;
+				return (enum vk_swizzle)x;
 		return VK_SWIZZLE_0;
 	case VK_COMPONENT_SWIZZLE_B:
 		for (x = 0; x < 4; x++)
 			if (chan[x] == 2)
-				return x;
+				return (enum vk_swizzle)x;
 		return VK_SWIZZLE_0;
 	case VK_COMPONENT_SWIZZLE_A:
 		for (x = 0; x < 4; x++)
 			if (chan[x] == 3)
-				return x;
+				return (enum vk_swizzle)x;
 		return VK_SWIZZLE_1;
 	default:
 		unreachable("Illegal swizzle");