target/cortex_a: allow command dacrfixup during init phase

target/cortex_a: allow command dacrfixup during init phase

There is no reason to restrict the command "cortex_a dacrfixup"
to the EXEC phase only.
Change the command mode to ANY so the command can be used in
the initialization phase too.

Change-Id: I498cc6b2dbdc48b3b2dd5f0445519a51857b295f
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/4623
Tested-by: jenkins
Reviewed-by: Matthias Welwarsky <matthias@welwarsky.de>