serial: 8250: Switch UART port flags to using BIT_ULL

Use BIT_ULL rather than encoding bits explicitly where applicable with
UART port flags.  This makes a (__force upf_t) cast redundant, but keep
it for visual consistency with the flags defined in terms of userspace
macros.

Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2209210007030.41633@angie.orcam.me.uk


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