southbridge/amd sb600, sb700 & sb900 spelling fixes

Trivial fixes, but the editor highlights them, and it's easy to go
through a bunch of files while I'm otherwise idle.

Change-Id: I31333742d9c90cf6d7ae3d2f324880ed53807d7f
Signed-off-by: Martin Roth <martin.roth@se-eng.com>
Reviewed-on: http://review.coreboot.org/7840
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>

src/southbridge/amd/sb700/sm.c

@@ -181,7 +181,7 @@ static void sm_init(device_t dev)
 	if ((REV_SB700_A11 == rev) || REV_SB700_A12 == rev) {
 		byte |= 1 << 0;
 	}
-	/*Set bit2 to 1, enable Io port 60h read/wrire SMi trapping and
+	/*Set bit2 to 1, enable Io port 60h read/write SMi trapping and
 	 *Io port 64h write Smi trapping. conflict with ps2 keyboard
 	 */
 	//byte |= 1 << 2 | 1 << 3 | 1 << 4;