[ARM] Feroceon: catch other Feroceon CPU IDs in head.S

Tweak the Feroceon match/mask in arch/arm/boot/compressed/head.S to
match a couple of newer Feroceon cores (such as the 88fr571vd with
CPU ID 0x56155710, and the 88fr131 with CPU ID 0x56251310) as well.

Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>