wil6210: add support for ucode tracing

The driver needs to expose RGF_USER_USAGE_2 register that contains
the offset of the ucode logging table.

Change-Id: Id6fb964d9c6099ef203c45cacb225af3f5a4a447
Signed-off-by: Ahmad Masri <amasri@codeaurora.org>
Signed-off-by: Maya Erez <merez@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Git-commit: 8454e72a3644c7f3617ed85be899291f344dba7f
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/kvalo/ath.git


Signed-off-by: Maya Erez <merez@codeaurora.org>