lib: Fix spelling

Change-Id: I999987af9cb44906e3c3135c0351a0cd6eb210ff
Signed-off-by: Martin Roth <martin.roth@se-eng.com>
Reviewed-on: http://review.coreboot.org/3756
Reviewed-by: Dave Frodin <dave.frodin@se-eng.com>
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/lib/fallback_boot.c

@@ -8,7 +8,7 @@
 
 static void set_boot_successful(void)
 {
-	/* Remember I succesfully booted by setting
+	/* Remember I successfully booted by setting
 	 * the initial boot direction
 	 * to the direction that I booted.
 	 */