This patch fixes UART system call authorization initialization (when
protection domain support is enabled) to only initialize the system call
entrypoint and authorization data structures once, prior to per-port
setup. Previously, if two UARTs were configured, the setup procedure for
the second UART would erase the system call authorization for the
first (console) UART, resulting in a crash upon the next attempt to
perform console output.
bde8eb35ae