ios-simulator: Disable Metal.

src/config.h

@@ -45,7 +45,7 @@
 
 #	ifndef BGFX_CONFIG_RENDERER_METAL
 #		define BGFX_CONFIG_RENDERER_METAL (0 \
-					||  BX_PLATFORM_IOS \
+					|| (BX_PLATFORM_IOS && BX_CPU_ARM) \
 					|| (BX_PLATFORM_OSX >= 101100) \
 					? 1 : 0)
 #	endif // BGFX_CONFIG_RENDERER_METAL