Change in coreboot[master]: lib/thread: Add thread_handle

[Julius Werner (Code Review)]

Attention is currently required from: Raul Rangel, Eric Peers, Felix Held.
Julius Werner has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/56229 )

Change subject: lib/thread: Add thread_handle
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Patch Set 5:

(4 comments)

File src/include/thread.h:

https://review.coreboot.org/c/coreboot/+/56229/comment/007e712d_2b88b2fe 
PS5, Line 69: wait_for_thread
nit: thread_wait() to keep with the namespace prefix?

https://review.coreboot.org/c/coreboot/+/56229/comment/eb0eade7_4dcf3eb9 
PS5, Line 111: 	return CB_ERR;
Could probably be dead_code()?

File src/lib/thread.c:

https://review.coreboot.org/c/coreboot/+/56229/comment/66a46bbb_edbb188e 
PS5, Line 408: 	printk(BIOS_DEBUG, "waiting for thread\n");
Same as with the mutex, I'm not sure these are super useful. If you want to keep them, maybe put a name string in the thread_handle to make them more expressive?

https://review.coreboot.org/c/coreboot/+/56229/comment/581d4f96_b259b3d4 
PS5, Line 411: 		thread_yield_microseconds(10);
Why not 0?