serial: imx: fix comment about which machines use the i.MX21 type
serial: imx: fix comment about which machines use the i.MX21 type

Signed-off-by: Uwe Kleine-König <181323dd666a182bc2d953e52d0ac3ab54cd8391@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <4645f7897fd33786a2ee1264d590b3c400559d85@linuxfoundation.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs