Different boards using u-boot SPL require to write to different
locations. Sometimes, the 8MiB gap isn't sufficient - rk3399 boards
write to 0x16384 for example, which is at 8MiB, thus overriding the
fat32 partition with the SPL.
(cherry picked from commit 1db54a5522a2d523e406ce8713bfe88bb9e3f657)
e453a9ed9b