MIPS: Loongson64: Include bootinfo.h in dma.c

dma.c defined function plat_swiotlb_setup, which is declared in
bootinfo.h.

Fixes warning:
arch/mips/loongson64/dma.c:25:13: warning: no previous prototype for ‘plat_swiotlb_setup’ [-Wmissing-prototypes]
   25 | void __init plat_swiotlb_setup(void)
      |             ^~~~~~~~~~~~~~~~~~
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/loongson64/dma.c

@@ -2,6 +2,7 @@
 #include <linux/dma-direct.h>
 #include <linux/init.h>
 #include <linux/swiotlb.h>
+#include <asm/bootinfo.h>
 #include <boot_param.h>
 
 dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)