target/aarch64: Call aarch64_init_debug_access() earlier in aarch64_deassert_reset()

target/aarch64: Call aarch64_init_debug_access() earlier in aarch64_deassert_reset()

On Renesas R-Car, calling 'reset halt' and 'reset init' always made DAP inaccessible. Calling 'reset' and 'halt' seperatly worked fine.
The only differences seems to be the point in time when aarch64_init_debug_access() is called. This patch aligns the behaviour.

Change-Id: I2296c65e48414a7d9846f12a395e5eca315b49ca
Signed-off-by: Dennis Ostermann <dennis.ostermann@renesas.com>
Reviewed-on: http://openocd.zylin.com/4607
Tested-by: jenkins
Reviewed-by: Matthias Welwarsky <matthias@welwarsky.de>