arch/tile: avoid a simulator warning during bootup

As the added comment says, we can sometimes see a coherence warning
from our simulator if the "swapper_pgprot" variable on the boot cpu
has not been evicted from cache by the time the other cpus come up.
Force it to be evicted so we never see the warning.
Signed-off-by: NChris Metcalf <cmetcalf@tilera.com>

arch/tile/mm/init.c

@@ -653,6 +653,17 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
 	memcpy(pgd_base, pgtables, sizeof(pgtables));
 	__install_page_table(pgd_base, __get_cpu_var(current_asid),
 			     swapper_pgprot);
+
+	/*
+	 * We just read swapper_pgprot and thus brought it into the cache,
+	 * with its new home & caching mode.  When we start the other CPUs,
+	 * they're going to reference swapper_pgprot via their initial fake
+	 * VA-is-PA mappings, which cache everything locally.  At that
+	 * time, if it's in our cache with a conflicting home, the
+	 * simulator's coherence checker will complain.  So, flush it out
+	 * of our cache; we're not going to ever use it again anyway.
+	 */
+	__insn_finv(&swapper_pgprot);
 }
 
 /*