Change in coreboot[master]: Add console deinit API, use in SMM handler

[Patrick Georgi (Code Review)]

Attention is currently required from: Nico Huber, Stefan Reinauer, Paul Menzel, Rocky Phagura, Christian Walter, Angel Pons, Arthur Heymans, Kyösti Mälkki, Peter Tsung Ho Wu, Deomid "rojer" Ryabkov, Ron Minnich.
Patrick Georgi has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/56386 )

Change subject: Add console deinit API, use in SMM handler
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Patch Set 11:

(1 comment)

Commit Message:

https://review.coreboot.org/c/coreboot/+/56386/comment/9ff1d452_19ab810c 
PS11, Line 14: on an OCP Delta Lake server: uart8250_init disables interrupts because it
> yes in coreboot stage it's fine, but this change is for entering and exiting smm while printing smm  […]

So uart8250_init() is called via console_init() in smi_handler() / smm_handler_start() (depending on which SMM modules are used or not).

Various things in the handler really should only be called the first time, and console_init belongs in that group IMHO: among other reasons because we don't want to see "\n\ncoreboot-%s%s %s " ENV_STRING " starting (log level: %i)...\n" emitted on every SMM. (see end of console_init() )

Our serial driver is simple enough that it should cope with most UART reconfiguration the OS might do while not actively using the serial port (in which case SMM should be configured not to interfere with OS talk on that line anyway)

+Stefan, do you remember what's going on here? What am I missing?