8250_tegra: clean up tegra_uart_handle_break

* switch "do { A; } while (1)" to "while (1) { A; }"
* switch "if (A) B; else break;" to "if (!A) break; B;"
* remove unused assignment from p->serial_in() to status

Objdump -d shows no difference.

Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210105120239.28031-6-jslaby@suse.cz


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