m68k: Document that access_ok is broken for !CONFIG_CPU_HAS_ADDRESS_SPACES

Document that access_ok is completely broken for coldfire and friends at
the moment.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Link: https://lore.kernel.org/r/20210916070405.52750-2-hch@lst.deSigned-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

arch/m68k/include/asm/uaccess.h

@@ -16,6 +16,10 @@
 static inline int access_ok(const void __user *addr,
 			    unsigned long size)
 {
+	/*
+	 * XXX: for !CONFIG_CPU_HAS_ADDRESS_SPACES this really needs to check
+	 * for TASK_SIZE!
+	 */
 	return 1;
 }