ARM: tegra: move fuse exports to soc/tegra/fuse.h

All fuse related functionality will move to a driver in the following
patches. To prepare for this, export all the required functionality in a
global header file and move all users of fuse.h to soc/tegra/fuse.h.

While we're at it, remove tegra_bct_strapping, as its only user was
removed in Commit a7cbe92c

 ("ARM: tegra: remove tegra EMC scaling
driver").

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>