ath10k: define structure for the copy engine misc regs

Define structures for the copy engine misc registers
copy engine CMD halt, watermark source, watermark
destination, host IE ring.

This adds support to avoid the conditional compilation,
code optimization and dynamic configuration of the copy
engine register map for respective hardware bus interface.

Change-Id: I42b9c0ad0927b492e3b4f040ae7163456b161735
Signed-off-by: Sarada Prasanna Garnayak <sgarna@codeaurora.org>