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/compute_ip_checksum.c

@@ -40,7 +40,7 @@ unsigned long add_ip_checksums(unsigned long offset, unsigned long sum, unsigned
 	new = ~new & 0xFFFF;
 	if (offset & 1) {
 		/* byte swap the sum if it came from an odd offset
-		 * since the computation is endian independant this
+		 * since the computation is endian independent this
 		 * works.
 		 */
 		new = ((new >> 8) & 0xff) | ((new << 8) & 0xff00);