arm926ejs: remove noop flush_dcache_all function

Commit 2f3427cc added noop cache functions implementation for arm926ejs
to fix compilation of drivers depending on these functions (DaVinci
EMAC in particular).

Unfortunately, the bug was introduced: noop implementation calls
dcache_disable which calls flush_dcache_all which in turn calls
dcache_disable thus creating an infinite loop.

This patch removes noop implementation for flush_dcache_all, we already
have default one in arch/arm/lib/cache.c and it should be used instead.
Signed-off-by: NIlya Yanok <yanok@emcraft.com>
Tested-by: NMatthias Weisser <weisserm@arcor.de>

arch/arm/cpu/arm926ejs/cache.c

@@ -38,11 +38,6 @@ void invalidate_dcache_all(void)
 	dcache_noop();
 }
 
-void flush_dcache_all(void)
-{
-	dcache_noop();
-}
-
 void invalidate_dcache_range(unsigned long start, unsigned long stop)
 {
 	dcache_noop();