ARC: mm: tlb flush optim: Make TLBWriteNI fallback to TLBWrite if not available

TLBWriteNI was introduced in MMUv2 (to not invalidate uTLBs in Fast Path
TLB Refill Handler). To avoid #ifdef'ery make it fallback to TLBWrite availabel on all MMUs. This will also help with next change

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

arch/arc/mm/tlbex.S

@@ -292,11 +292,7 @@ ex_saved_reg1:
 	sr  TLBGetIndex, [ARC_REG_TLBCOMMAND]
 
 	/* Commit the Write */
-#if (CONFIG_ARC_MMU_VER >= 2)   /* introduced in v2 */
 	sr TLBWriteNI, [ARC_REG_TLBCOMMAND]
-#else
-	sr TLBWrite, [ARC_REG_TLBCOMMAND]
-#endif
 
 #else
 	sr TLBInsertEntry, [ARC_REG_TLBCOMMAND]