src: change coreboot to lowercase

The word 'coreboot' should always be written in lowercase, even at the
start of a sentence.

Change-Id: I7945ddb988262e7483da4e623cedf972380e65a2
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/20029
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Philippe Mathieu-Daudé <philippe.mathieu.daude@gmail.com>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/lib/selfboot.c

@@ -73,7 +73,7 @@ static void segment_insert_after(struct segment *seg, struct segment *new)
  *
  * Benefits:
  * - Nearly arbitrary standalone executables can be loaded.
- * - Coreboot is preserved, so it can be returned to.
+ * - coreboot is preserved, so it can be returned to.
  * - The implementation is still relatively simple,
  *   and much simpler than the general case implemented in kexec.
  */