mimxrt/machine_uart: Fix and complete UART.deinit and uart_deinit_all.

The code did not check at deinit whether a UART was initialized.  That did
not matter for all MCU's except MIMXRT1176, which crashes at the second
soft reset in a row.

But since it is a general problem to use UART methods of a UART which has
been deinitialized, checks were added to all applicable methods for a clear
response instead of e.g. a crash.

Deinitialize UART using software reset.  It resets the UART but keeps it
accessible for software, avoiding an exception when UART registers are
accessed after a DeInit.

Signed-off-by: robert-hh <robert@hammelrath.com>

0 files changed, 0 insertions, 0 deletions