x86: add the DFF (Desktop Form Factor) Dell Optiplex 745 to the reboot errata list

We recently got some of the "Desktop Form Factor" Optiplex 745's in.  I
noticed that there's an entry for the SFF one's, but the BIOS model number
of the DFF differs from that of the SFF.  We have been reliably
experiencing the same (as far as I can tell) reboot bug as the SFF boxes.

Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>