Change in coreboot[master]: arch/x86: Add a common romstage entry

[Felix Held (Code Review)]

Attention is currently required from: Jason Glenesk, Nico Huber, Furquan Shaikh, Marshall Dawson, Angel Pons, Arthur Heymans, Fred Reitberger, Patrick Rudolph.
Felix Held has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/55067 )

Change subject: arch/x86: Add a common romstage entry
......................................................................

Patch Set 13:

(1 comment)

File src/cpu/intel/car/romstage.c:

https://review.coreboot.org/c/coreboot/+/55067/comment/cc1fea32_af16fee7 
PS13, Line 58: 	/* We do not return here. */
             : 	die("failed to load postcar\n");
             :
> Shouldn't we move this to common code too?

printing "failed to load next stage" in the new car_stage_entry function after the romstage_main call would also avoid the need for the __noreturn attribute for romstage_main. i'm ok with doing this in a follow-up, but marking as not resolved to make sure that the change won't be overlooked; nearly submitted this one even though this is sounds like a good improvement to me