microblaze: Use predefined SYSCALL_DEFINE macro

Use standard syscall definition.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/microblaze/kernel/sys_microblaze.c

@@ -33,9 +33,9 @@
 #include <linux/slab.h>
 #include <asm/syscalls.h>
 
-asmlinkage long sys_mmap(unsigned long addr, unsigned long len,
-			unsigned long prot, unsigned long flags,
-			unsigned long fd, off_t pgoff)
+SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
+		unsigned long, prot, unsigned long, flags, unsigned long, fd,
+		off_t, pgoff)
 {
 	if (pgoff & ~PAGE_MASK)
 		return -EINVAL;