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/drivers/intel/fsp1_1/raminit.c

@@ -277,7 +277,7 @@ void raminit(struct romstage_params *params)
 
 	/* Verify the FSP 1.1 HOB interface */
 	if (fsp_verification_failure)
-		die("ERROR - Coreboot's requirements not met by FSP binary!\n");
+		die("ERROR - coreboot's requirements not met by FSP binary!\n");
 
 	/* Display the memory configuration */
 	report_memory_config();