UPF_MAGIC_MULTIPLIER is userspace available bit and can be changed
at any time. There is no sense to rely on it to be always present.

This reverts commit b4ccaf5a.

Note, that code was not reliably worked before, hence it implies
no functional change.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Fixes: b4ccaf5a ("serial: 8250_pericom: Re-enable higher baud rates")
Link: https://lore.kernel.org/r/20220203150026.19087-1-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>