ARM: ensure C page table setup code follows assembly code

Fix a long standing bug where, for ARMv6+, we don't fully ensure that
the C code sets the same cache policy as the assembly code.  This was
introduced partially by commit 11179d8ca2 ([ARM] 4497/1: Only allow
safe cache configurations on ARMv6 and later) and also by adding SMP
support.

This patch sets the default cache policy based on the flags used by the
assembly code, and then ensures that when a cache policy command line
argument is used, we verify that on ARMv6, it matches the initial setup.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/setup.c

@@ -72,6 +72,7 @@ static int __init fpe_setup(char *line)
 __setup("fpe=", fpe_setup);
 #endif
 
+extern void init_default_cache_policy(unsigned long);
 extern void paging_init(const struct machine_desc *desc);
 extern void early_paging_init(const struct machine_desc *,
 			      struct proc_info_list *);
@@ -603,7 +604,9 @@ static void __init setup_processor(void)
 #ifndef CONFIG_ARM_THUMB
 	elf_hwcap &= ~(HWCAP_THUMB | HWCAP_IDIVT);
 #endif
-
+#ifdef CONFIG_MMU
+	init_default_cache_policy(list->__cpu_mm_mmu_flags);
+#endif
 	erratum_a15_798181_init();
 
 	feat_v6_fixup();