ppc flush_cache: add watch-dog triggering into the loops.

Some boards (e.g. lwmon5) need rather a frequent watch-dog
kicking. Since the time it takes for the flush_cache() function
to complete its job depends on the size of data being flushed, one
may encounter watch-dog resets on such boards when, for example,
download big files over ethernet.

Signed-off-by: Yuri Tikhonov <yur@emcraft.com>

lib_ppc/cache.c

diff --git a/lib_ppc/cache.c b/lib_ppc/cache.c
index 27e1a82..5bfb220 100644
--- a/lib_ppc/cache.c
+++ b/lib_ppc/cache.c
@@ -23,6 +23,7 @@
 
 #include <common.h>
 #include <asm/cache.h>
+#include <watchdog.h>
 
 void flush_cache (ulong start_addr, ulong size)
 {
@@ -35,6 +36,7 @@
 		     addr < end_addr;
 		     addr += CFG_CACHELINE_SIZE) {
 			asm ("dcbst 0,%0": :"r" (addr));
+			WATCHDOG_RESET();
 		}
 		asm ("sync");	/* Wait for all dcbst to complete on bus */
 
@@ -42,6 +44,7 @@
 		     addr < end_addr;
 		     addr += CFG_CACHELINE_SIZE) {
 			asm ("icbi 0,%0": :"r" (addr));
+			WATCHDOG_RESET();
 		}
 	}
 	asm ("sync");		/* Always flush prefetch queue in any case */