jtag: fix command "adapter [de]assert" with dap direct

jtag: fix command "adapter [de]assert" with dap direct

The commit fafe6dfc9cd8 ("adapter: add command "adapter [de]assert
srst|trst [[de]assert srst|trst]"") was proposed in gerrit well
before commit a61ec3c1d73d ("adi_v5_dapdirect: add support for
adapter drivers that provide DAP API") get merged, so it didn't
include a complete support for dap direct.
The merge upstream of the two commits lacks the support by command
"adapter [de]assert" for dap direct

Let command command "adapter [de]assert" handle dap direct.

Change-Id: I1a69f8ee877c8fd57598ed4ad9d71da61d15457c
Fixes: commit fafe6dfc9cd8 ("adapter: add command "adapter [de]assert srst|trst [[de]assert srst|trst]"")
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/5515
Tested-by: jenkins
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>