xtensa: nommu: don't provide arch_get_unmapped_area

Nommu unconditionally provides arch_get_unmapped_area that always
returns -ENOMEM.

Signed-off-by: Max Filippov <[e-mail]>

arch/xtensa/kernel/syscall.c

···
 	return sys_fadvise64_64(fd, offset, len, advice);
 }
 
+#ifdef CONFIG_MMU
 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
 		unsigned long len, unsigned long pgoff, unsigned long flags)
 {
···
 			addr = COLOUR_ALIGN(addr, pgoff);
 	}
 }
+#endif