Revert "sh: Kill off now redundant local irq disabling."

This reverts commit 64a6d72213dd810dd55bd0a503c36150af41c3c3.

Unfortunately we can't use on_each_cpu() for all of the cache ops, as
some of them only require preempt disabling. This seems to be the same
issue that impacts the mips r4k caches, where this code was based on.
This fixes up a deadlock that showed up in some IRQ context cases.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/mm/cache-sh7705.c b/arch/sh/mm/cache-sh7705.c
index 9dc3866..6293f57 100644
--- a/arch/sh/mm/cache-sh7705.c
+++ b/arch/sh/mm/cache-sh7705.c
@@ -81,6 +81,7 @@
 static void __flush_dcache_page(unsigned long phys)
 {
 	unsigned long ways, waysize, addrstart;
+	unsigned long flags;
 
 	phys |= SH_CACHE_VALID;
 
@@ -97,6 +98,7 @@
 	 * potential cache aliasing, therefore the optimisation is probably not
 	 * possible.
 	 */
+	local_irq_save(flags);
 	jump_to_uncached();
 
 	ways = current_cpu_data.dcache.ways;
@@ -124,6 +126,7 @@
 	} while (--ways);
 
 	back_to_cached();
+	local_irq_restore(flags);
 }
 
 /*
@@ -142,9 +145,14 @@
 
 static void sh7705_flush_cache_all(void *args)
 {
+	unsigned long flags;
+
+	local_irq_save(flags);
 	jump_to_uncached();
+
 	cache_wback_all();
 	back_to_cached();
+	local_irq_restore(flags);
 }
 
 /*