drivers: serial: stm32: expand DMAT errata test.

I manually checked the errata sheets for all STM32Hxx/STM32Uxx parts to
confirm the defect's presence or absence. It appears to have been resolved
in silicon on newer parts (e.g., STM32U3xx family), so hopefully this test
will not need grow further (knock on wood).

Co-authored-by: Nicolas Zuluaga <nicolas.zuluaga@rbr-global.com>
Signed-off-by: Samuel Coleman <samuel.coleman@rbr-global.com>