ARC: [mm] Prevent stray dcache lines after__sync_icache_dcach()

Flush and INVALIDATE the dcache page.

This helper is only used for writeback of CODE pages to memory. So
there's no value in keeping the dcache lines around. Infact it is risky
as a writeback on natural eviction under pressure can cause un-needed
writeback with weird issues on aliasing dcache configurations.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
diff --git a/arch/arc/mm/cache_arc700.c b/arch/arc/mm/cache_arc700.c
index 2f12bca..d4b7bb6 100644
--- a/arch/arc/mm/cache_arc700.c
+++ b/arch/arc/mm/cache_arc700.c
@@ -610,7 +610,7 @@
 
 	local_irq_save(flags);
 	__ic_line_inv_vaddr(paddr, vaddr, len);
-	__dc_line_op(paddr, vaddr, len, OP_FLUSH);
+	__dc_line_op(paddr, vaddr, len, OP_FLUSH_N_INV);
 	local_irq_restore(flags);
 }