ath6kl: enable firmware crash dumps on the AR6004

The firmware crash dumps on the 6004 are the same as the 6003. Remove the
statement guarding it from dumping on the 6004.  Renamed the
REG_DUMP_COUNT_AR6003 to reflect support on both chips.

Signed-off-by: Dan Kephart <dan.kephart@lairdtech.com>
Reviewed-by: Steve deRosier <steve.derosier@lairdtech.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>