Change in coreboot[master]: superio/aspeed: setup early serial for AST2600

[Paul Menzel (Code Review)]

Attention is currently required from: Jonathan Zhang, Stefan Reinauer, David Hendricks, Angel Pons, Subrata Banik, TsungHo Wu, Kyösti Mälkki, Patrick Rudolph, ron minnich.
Paul Menzel has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/50374 )

Change subject: superio/aspeed: setup early serial for AST2600
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Patch Set 4:

(3 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/50374/comment/a2ba76dd_8dbd485f 
PS4, Line 7: setup
Set up

https://review.coreboot.org/c/coreboot/+/50374/comment/061a6c9e_8816cd2c 
PS4, Line 23: Change-Id: Ib21b054bea2e64e00521807e8aa13e536f643974
Please move this right above the Signed-off-by lines.

File src/superio/aspeed/ast2400/ast2400.h:

https://review.coreboot.org/c/coreboot/+/50374/comment/d21b28e4_d2c30825 
PS4, Line 16: #define AST2600_CHIP_ID_REG     0x20
Please align with tabs as above?