drivers/usb/serial: refactor min with min_t

Ensure type safety by using min_t() instead of casted min().

Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
Link: https://lore.kernel.org/r/20241112155817.3512577-8-snovitoll@gmail.com


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