cortex-a: fix reset on dapdirect transports

cortex-a: fix reset on dapdirect transports

The target code for assert reset on cortex_a has been patched on
commit b0698501b0e7 ("cortex_a: fix cortex_a_assert_reset() if
srst_gates_jtag") then in cdba6ba0ad63 ("cortex_a: fix reset for
SWD transport") to workaround the mismatch between jtag and swd
implementations. See discussion for the second patch at
http://openocd.zylin.com/3641/

While all of these mismatches should hopefully be cleaned by the
reset framework rework, an extension of the workaround of the
second patch is required for dapdirect transports, either
dapdirect_swd and dapdirect_jtag.

Extend the existing workaround to all non-jtag transports.

Change-Id: Ia6a9d43bab524cbb3de4c37ce24c45f25187353d
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/5979
Tested-by: jenkins