roms: Update vbootrom to 1287b6e

This newer vbootrom supports NPCM8xx. Similar to the NPCM7XX one
it supports loading the UBoot from the SPI device and not more.

We updated the npcm7xx bootrom to be compiled from this version.

Reviewed-by: Peter Maydell <[email protected]>
Signed-off-by: Hao Wu <[email protected]>
Message-id: [email protected]
Signed-off-by: Peter Maydell <[email protected]>

Author: haowu4682