adi_v5_swd: Avoid special handling the SELECT cache during connect

adi_v5_swd: Avoid special handling the SELECT cache during connect

The cache is forced to zero to match the value expected by the DPIDR read
so the connect sequence is not destroyed by a SELECT update.

However, DPIDR and in fact all registers except address 4 are independent
of the current DPBANKSEL value. Change swd_queue_dp_bankselect() to use
this fact and avoid touching SELECT for those registers.

Change-Id: I0cd11925fb6adef481bbf45cc24ea2c6dab4b6fb
Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-on: http://openocd.zylin.com/3231
Tested-by: jenkins
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>