nios2: rework cache

- flush dcache before flush instruction cache
- remork update_mmu_cache and flush_dcache_page
- add shmparam.h

Signed-off-by: Ley Foon Tan <lftan@altera.com>

arch/nios2/include/asm/shmparam.h

@@ -0,0 +1,21 @@
+/*
+ * Copyright Altera Corporation (C) <2015>. All rights reserved
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef _ASM_NIOS2_SHMPARAM_H
+#define _ASM_NIOS2_SHMPARAM_H
+
+#define	SHMLBA	CONFIG_NIOS2_DCACHE_SIZE
+
+#endif /* _ASM_NIOS2_SHMPARAM_H */