ARM: tegra: Restore DRAM bank count

ARM: tegra: Restore DRAM bank count

Commit 86cf1c82850f ("configs: Migrate CONFIG_NR_DRAM_BANKS") reduced
the number of DRAM banks supported by U-Boot from 1026 to 8 on P2771-000
boards.

However, as explained in commit a9819b9e33bd ("ARM: tegra: p2771-000:
increase max DRAM bank count"), the platform can have a large number of
unusable chunks of memory (up to 1024), so a total of 1026 DRAM banks
are needed to describe the worst-case situation.

In practice the number of DRAM banks needed will typically be much
lower, but we should be prepared to properly deal with the worst case.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>