soc/tegra: fuse: fix dummy functions

The Tegra fuse header's dummy functions for the case where Tegra20 is
disabled are inconsistent with the correct prototypes, and have some
syntax errors. Fix these. While at it, fix the indentation level of
the dummy function bodies.

Fixes: 783c8f4c

 ("soc/tegra: Add efuse driver for Tegra")
Cc: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>