ARM: tegra: switch FUSE clock on before usage

FUSE clock is enabled by most bootloaders, but we cannot expect it to be
on in all contexts (e.g. kexec).

Ensure the FUSE clock is enabled before any of its registers is touched.
Since FUSE is touched very early during system boot (before the clock
devices are registered), directly manipulate the clock register bit in
case the clock device cannot be acquired.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>