drm/tegra: hub: Use fn parameter directly to fix Coccinelle warning

drm/tegra: hub: Use fn parameter directly to fix Coccinelle warning

The function parameter out can be used directly instead of assigning it
to a temporary u64 variable first.

Remove the local variable tmp2 and use the parameter out directly as the
divisor in do_div() to remove the following Coccinelle/coccicheck
warning reported by do_div.cocci:

  WARNING: do_div() does a 64-by-32 division, please consider using div64_u64 instead

Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240710210034.796032-2-thorsten.blum@toblux.com