ARC: Remove ARC_HAS_COH_RTSC

The symbol is an orphan, get rid of it.

Fixes: 7d0857a54aed ("ARC: [SMP] Disallow RTSC")
Signed-off-by: Richard Weinberger <richard@nod.at>
Acked-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

arch/arc/plat-arcfpga/Kconfig

@@ -33,7 +33,6 @@ config ISS_SMP_EXTN
 	bool "ARC SMP Extensions (ISS Models only)"
 	default n
 	depends on SMP
-	select ARC_HAS_COH_RTSC
 	help
 	  SMP Extensions to ARC700, in a "simulation only" Model, supported in
 	  ARC ISS (Instruction Set Simulator).