newdap: Ignore -irlen/-irmask/etc newdap params on SWD or CMSIS-DAP

newdap: Ignore -irlen/-irmask/etc newdap params on SWD or CMSIS-DAP

Previously the -irlen parameter was required even though it is not
a part of the SWD or CMSIS-DAP transports.

This may eventually need to be changed for CMSIS-DAP once that
supports JTAG as well.

Change-Id: Ia02b67840c19c7cf1c7a75063648c0174176a311
Signed-off-by: Angus Gratton <gus@projectgus.com>
Reviewed-on: http://openocd.zylin.com/2226
Tested-by: jenkins
Reviewed-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>