[Blackfin] arch: fix wrong header name in comment

Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

arch/blackfin/kernel/fixed_code.S

@@ -1,6 +1,6 @@
 /*
  * This file contains sequences of code that will be copied to a
- * fixed location, defined in <asm/atomic_seq.h>.  The interrupt
+ * fixed location, defined in <asm/fixed_code.h>.  The interrupt
  * handlers ensure that these sequences appear to be atomic when
  * executed from userspace.
  * These are aligned to 16 bytes, so that we have some space to replace