[AArch64] Implement stfiwx

Improves povray performance by ~4%

Source/Core/Core/PowerPC/JitArmCommon/BackPatch.h

@@ -19,6 +19,7 @@ struct BackPatchInfo
 		FLAG_REVERSE  = (1 << 7),
 		FLAG_EXTEND   = (1 << 8),
 		FLAG_ONLY_LOWER = (1 << 9),
+		FLAG_SIZE_F32I = (1 << 10),
 	};
 
 	static u32 GetFlagSize(u32 flags)
@@ -29,7 +30,7 @@ struct BackPatchInfo
 			return 16;
 		if (flags & FLAG_SIZE_32)
 			return 32;
-		if (flags & FLAG_SIZE_F32)
+		if (flags & FLAG_SIZE_F32 || flags & FLAG_SIZE_F32I)
 			return 32;
 		if (flags & FLAG_SIZE_F64)
 			return 64;