MIPS: bmips: Fix compiler warning observed on W=1 build

The function arch_sync_dma_for_cpu_all() was used but was
missing a prototype declaration.

Signed-off-by: Jim Quinlan <[e-mail]>
Reported-by: kernel test robot <[e-mail]>
Acked-by: Florian Fainelli <[e-mail]>
Signed-off-by: Thomas Bogendoerfer <[e-mail]>

arch/mips/bmips/dma.c

···
 // SPDX-License-Identifier: GPL-2.0+
 
 #include <linux/types.h>
+#include <linux/dma-map-ops.h>
 #include <asm/bmips.h>
 #include <asm/io.h>