ARC: [plat-sim] Include this platform unconditionally

Essentially remove CONFIG_ARC_PLAT_SIM

There is no need for any platform specific code, just the board DTS
match strings which we can include unconditionally

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

arch/arc/plat-sim/platform.c

@@ -20,11 +20,14 @@
  */
 
 static const char *simulation_compat[] __initconst = {
+#ifdef CONFIG_ISA_ARCOMPACT
 	"snps,nsim",
-	"snps,nsim_hs",
 	"snps,nsimosci",
+#else
+	"snps,nsim_hs",
 	"snps,nsimosci_hs",
 	"snps,zebu_hs",
+#endif
 	NULL,
 };