char/adi: Remove redundant less-than-zero check in adi_write()

The function parameter 'size_t count' is unsigned and cannot be less
than zero. Remove the redundant condition.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Link: https://lore.kernel.org/r/20250903202350.182446-2-thorsten.blum@linux.dev


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>