HACK: ARM: OMAP4470: wakeupgen: Enable ROM_CPU1_BACKUP errata

Commit 6a9c42c3f84fad476200a6e19e106ba3eea9787b
("ARM: OMAP4460: wakeupgen: set GIC_CPU0 backup status flag always")
introduced a fix for OMAP4460 ROM code bug.
The bug causes CPU0 crash in the ROM code during wakeup
from device off because of GIC resisters corruption.

This ROM code bug should be fixed in OMAP4470,
but we observe similar crash of CPU0 on wakeup.
Extending the errata WA to 4470 fixes CPU0 wakeup.
So enable it until the real rootcause is found.

Change-Id: I09744623e511042e2641489eb50f8a7178b43356
Signed-off-by: Taras Kondratiuk <taras@ti.com>